US20200230533A1 - Filter device - Google Patents
Filter device Download PDFInfo
- Publication number
- US20200230533A1 US20200230533A1 US16/840,511 US202016840511A US2020230533A1 US 20200230533 A1 US20200230533 A1 US 20200230533A1 US 202016840511 A US202016840511 A US 202016840511A US 2020230533 A1 US2020230533 A1 US 2020230533A1
- Authority
- US
- United States
- Prior art keywords
- case
- filter medium
- filter
- tubular
- tubular portion
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000001914 filtration Methods 0.000 abstract description 27
- 239000000428 dust Substances 0.000 abstract description 20
- 239000007788 liquid Substances 0.000 abstract description 11
- 239000010720 hydraulic oil Substances 0.000 description 115
- 239000003921 oil Substances 0.000 description 31
- 238000012986 modification Methods 0.000 description 11
- 230000004048 modification Effects 0.000 description 11
- 230000012447 hatching Effects 0.000 description 10
- 230000007423 decrease Effects 0.000 description 3
- 238000005192 partition Methods 0.000 description 3
- 230000002093 peripheral effect Effects 0.000 description 3
- 238000007789 sealing Methods 0.000 description 3
- 238000002485 combustion reaction Methods 0.000 description 2
- 230000003628 erosive effect Effects 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 1
- 210000000078 claw Anatomy 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000014509 gene expression Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 239000000057 synthetic resin Substances 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
- B01D29/11—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with bag, cage, hose, tube, sleeve or like filtering elements
- B01D29/13—Supported filter elements
- B01D29/15—Supported filter elements arranged for inward flow filtration
- B01D29/21—Supported filter elements arranged for inward flow filtration with corrugated, folded or wound sheets
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D35/00—Filtering devices having features not specifically covered by groups B01D24/00 - B01D33/00, or for applications not specifically covered by groups B01D24/00 - B01D33/00; Auxiliary devices for filtration; Filter housing constructions
- B01D35/005—Filters specially adapted for use in internal-combustion engine lubrication or fuel systems
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D27/00—Cartridge filters of the throw-away type
- B01D27/10—Safety devices, e.g. by-passes
- B01D27/106—Anti-leakage or anti-return valves
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
- B01D29/11—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with bag, cage, hose, tube, sleeve or like filtering elements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
- B01D29/11—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with bag, cage, hose, tube, sleeve or like filtering elements
- B01D29/13—Supported filter elements
- B01D29/15—Supported filter elements arranged for inward flow filtration
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
- B01D29/60—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor integrally combined with devices for controlling the filtration
- B01D29/606—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor integrally combined with devices for controlling the filtration by pressure measuring
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
- B01D29/60—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor integrally combined with devices for controlling the filtration
- B01D29/608—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor integrally combined with devices for controlling the filtration by temperature measuring
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D35/00—Filtering devices having features not specifically covered by groups B01D24/00 - B01D33/00, or for applications not specifically covered by groups B01D24/00 - B01D33/00; Auxiliary devices for filtration; Filter housing constructions
- B01D35/02—Filters adapted for location in special places, e.g. pipe-lines, pumps, stop-cocks
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D35/00—Filtering devices having features not specifically covered by groups B01D24/00 - B01D33/00, or for applications not specifically covered by groups B01D24/00 - B01D33/00; Auxiliary devices for filtration; Filter housing constructions
- B01D35/02—Filters adapted for location in special places, e.g. pipe-lines, pumps, stop-cocks
- B01D35/027—Filters adapted for location in special places, e.g. pipe-lines, pumps, stop-cocks rigidly mounted in or on tanks or reservoirs
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D35/00—Filtering devices having features not specifically covered by groups B01D24/00 - B01D33/00, or for applications not specifically covered by groups B01D24/00 - B01D33/00; Auxiliary devices for filtration; Filter housing constructions
- B01D35/02—Filters adapted for location in special places, e.g. pipe-lines, pumps, stop-cocks
- B01D35/027—Filters adapted for location in special places, e.g. pipe-lines, pumps, stop-cocks rigidly mounted in or on tanks or reservoirs
- B01D35/0276—Filtering elements with a vertical rotation or symmetry axis mounted on tanks or reservoirs
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D35/00—Filtering devices having features not specifically covered by groups B01D24/00 - B01D33/00, or for applications not specifically covered by groups B01D24/00 - B01D33/00; Auxiliary devices for filtration; Filter housing constructions
- B01D35/14—Safety devices specially adapted for filtration; Devices for indicating clogging
- B01D35/147—Bypass or safety valves
- B01D35/1475—Pressure relief valves or pressure control valves
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D35/00—Filtering devices having features not specifically covered by groups B01D24/00 - B01D33/00, or for applications not specifically covered by groups B01D24/00 - B01D33/00; Auxiliary devices for filtration; Filter housing constructions
- B01D35/14—Safety devices specially adapted for filtration; Devices for indicating clogging
- B01D35/153—Anti-leakage or anti-return valves
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D35/00—Filtering devices having features not specifically covered by groups B01D24/00 - B01D33/00, or for applications not specifically covered by groups B01D24/00 - B01D33/00; Auxiliary devices for filtration; Filter housing constructions
- B01D35/30—Filter housing constructions
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D35/00—Filtering devices having features not specifically covered by groups B01D24/00 - B01D33/00, or for applications not specifically covered by groups B01D24/00 - B01D33/00; Auxiliary devices for filtration; Filter housing constructions
- B01D35/30—Filter housing constructions
- B01D35/306—Filter mounting adapter
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2201/00—Details relating to filtering apparatus
- B01D2201/04—Supports for the filtering elements
- B01D2201/0415—Details of supporting structures
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2201/00—Details relating to filtering apparatus
- B01D2201/04—Supports for the filtering elements
- B01D2201/043—Filter tubes connected to plates
- B01D2201/0446—Filter tubes connected to plates suspended from plates at the upper side of the filter elements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2201/00—Details relating to filtering apparatus
- B01D2201/04—Supports for the filtering elements
- B01D2201/0461—Springs
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2201/00—Details relating to filtering apparatus
- B01D2201/16—Valves
- B01D2201/167—Single-way valves
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2201/00—Details relating to filtering apparatus
- B01D2201/30—Filter housing constructions
- B01D2201/301—Details of removable closures, lids, caps, filter heads
Definitions
- the present invention relates to a filter device.
- Patent Document 1 discloses a filter device installed to an oil tank.
- hydraulic oil before being filtered flows from a flow path in a hydraulic circulation circuit to the filter device, the hydraulic oil is filtered through a filter element, and the hydraulic oil after filtration flows from the filter device into the oil tank.
- Patent Document 1 JP 2006-046142 A
- the filter element is provided inside a housing, and an opening in an upper end of the housing is covered with a lid member.
- the lid member is removed from the housing to replace the filter element via the opening.
- the hydraulic oil before filtration remains inside the housing or the filter element. This possibly causes the hydraulic oil and dust before filtration to flow out to the oil tank.
- One or more embodiments of the present invention is to provide a filter device that allows avoiding liquid and dust before filtration to flow out to a tank during replacement of a filter element.
- a filter device includes a case, a filter element, a lid body, an inflow portion, and an outflow portion.
- the case has a substantially bottomed tubular shape with an open upper end.
- the filter element having a substantially cylindrical shape is provided inside the case.
- the filter element includes a filter medium having a substantially cylindrical shape, an outer tube portion, and an upper plate.
- the outer tube portion includes a plate-like (plate-shaped) portion and a tubular portion.
- the plate-shaped portion has a substantially circular plate shape and is provided along a lower end surface of the filter medium.
- the tubular portion is provided outside the filter medium to be substantially parallel to the filter medium.
- the upper plate has a part with a substantially circular plate shape and is provided so as to cover upper end surfaces of the filter medium and the outer tube portion.
- the lid body is provided on the case and the upper plate so as to cover an upper end of the case.
- the inflow portion communicates between a space inside the case and outside the filter element and a space outside the case.
- the outflow portion communicates between a space inside the filter element and the space outside the case.
- the outflow portion is provided so as to penetrate a bottom surface of the case.
- the case includes a first tubular portion and a second tubular portion provided on a lower side of the first tubular portion.
- the second tubular portion has a diameter smaller than a diameter of the first tubular portion.
- the inflow portion is provided in the first tubular portion.
- the plate-shaped portion abuts on the bottom surface of the case and the tubular portion abuts on the second tubular portion.
- a part abutting on the second tubular portion of the tubular portion is absent of a hole.
- a part without abutment on the second tubular portion of the tubular portion has a plurality of holes.
- the case includes the first tubular portion and the second tubular portion positioned with the lower side of the first tubular portion.
- the second tubular portion has the diameter smaller than that of the first tubular portion.
- the tubular portion of the filter element abuts on the second tubular portion.
- the part abutting on the second tubular portion of the tubular portion is absent of the hole.
- the part without abutment on the second tubular portion of the tubular portion has the plurality of holes. Therefore, filtered dust accumulates between the filter medium and the tubular portion.
- liquid before filtration does not accumulate between the filter element and the case. This allows avoiding the liquid and the dust before filtration to flow out to a tank during replacement of the filter element.
- the lid body may have a first hole that communicates between a space inside the case and the space outside the case. Accordingly, air flows into the inside of the case through the first hole, thus ensuring discharging the liquid from the case and gradually lowering an oil surface without removing the lid body from the case. As a result, when the filter element is replaced, oil is drained from the filter element, and therefore a drip of the liquid to an outside of the filter device can be avoided.
- the filter device may be configured as follows.
- the case is provided inside a tank.
- the lid body is provided on an upper side of the tank.
- the first hole has a substantially U shape and has both ends opening to a surface on a lower side of the lid body.
- the first hole communicates between the space inside the filter element and a space outside the case and inside the tank. Accordingly, after a certain amount of period (for example, approximately five minutes) has passed after a work machine where the tank is provided stops, all of the liquid stored in the case can be discharged to the tank. Furthermore, the hydraulic oil after filtration that has not flown out from the outflow portion can be flown out to a tank via the first hole.
- the outer tube portion may be integrated with the filter medium so as to provide a clearance between the tubular portion and the filter medium.
- the space for accumulating the dust can be sufficiently ensured between the tubular portion and the filter medium.
- the filter device may be configured as follows.
- the lid body includes a flange portion and a cover.
- the flange portion having a substantially cylindrical shape is fixed to the case.
- the cover is detachably provided so as to cover a hollow portion of the flange portion.
- a sensor is attached to the flange portion. This eliminates the need for removing the sensor during replacement of the filter element, and maintenance can be facilitated.
- the filter device may be configured as follows.
- the filter element includes an inner tube provided inside the filter medium.
- the case or the filter element includes a tubular member provided inside the filter medium.
- the tubular member has a lower end positioned at substantially a same height as a lower end of the filter medium or a lower side with respect to the lower end of the filter medium.
- the tubular member has a diameter smaller than a diameter of the inner tube.
- the tubular member has a height lower than heights of the inner tube and the filter medium. This causes the hydraulic oil to flow upward along the tubular member and is guided to an upper portion of the filter medium. As a result, a filtration area of the filter medium can be effectively used.
- initial air can be effectively removed.
- the tubular member may have a drain hole adjacent to the plate-shaped portion. Accordingly, while a work machine stops, the hydraulic oil present outside the tubular portion can be discharged via the drain hole, and the oil surface in the case can be lowered.
- One or more embodiments of the present invention allows avoiding the liquid and the dust before filtration to flow out to the tank during replacement of the filter element.
- FIG. 1 is a perspective view of a main part illustrating an overview of a tank 100 in which a return filter 1 according to one embodiment of the present invention is provided.
- FIG. 2 is a cross-sectional view illustrating an overview of the return filter 1 .
- FIG. 3 is a cross-sectional view illustrating an overview of a filter element 20 .
- FIGS. 4A and 4B are perspective views of a main part illustrating an overview of a conventional return filter 110 , FIG. 4A illustrates its state during use, and FIG. 4B illustrates a state while a filter element is replaced.
- FIGS. 5A and 5B are drawings illustrating modifications of an outer tube portion
- FIG. 5A is a partially enlarged view of an outer tube portion 22 A according to Modification Example 1
- FIG. 5B is a partially enlarged view of an outer tube portion 22 B according to Modification Example 2.
- FIG. 6 is a cross-sectional view illustrating an overview of a return filter 2 .
- FIG. 7 is a cross-sectional view illustrating an overview of the return filter 2 .
- FIG. 8 is a cross-sectional view illustrating an overview of a return filter 3 .
- FIG. 9 is a cross-sectional view illustrating an overview of a check valve 65 .
- FIG. 10 is a cross-sectional view taken along the line B-B in FIG. 9 .
- FIGS. 11A and 11B are drawings illustrating an overview of a check valve 53 , FIG. 11A is its vertical cross-sectional view, and FIG. 11B is a cross-sectional view taken along the line A-A in FIG. 11A .
- FIGS. 12A and 12B are drawings illustrating an overview of a check valve 53 A, FIG. 12A is its vertical cross-sectional view, and FIG. 12B is a cross-sectional view taken along the line C-C in FIG. 12A .
- FIG. 13 is a cross-sectional view illustrating an overview of a return filter 4 .
- FIG. 14 is a cross-sectional view illustrating an overview of a return filter 4 A.
- FIG. 1 is a cross-sectional view illustrating an overview of a tank 100 in which a return filter 1 according to one embodiment of the present invention is provided.
- FIG. 1 hatching for indicating a cross section is omitted.
- the tank 100 is a tank for storing hydraulic oil.
- the tank 100 is installed in the work machine (not illustrated) (e.g., a hydraulic device), and is provided in a hydraulic circuit of hydraulic oil supplied to the hydraulic device.
- the tank 100 is not limited to one provided in the hydraulic circuit.
- the tank 100 is, for example, formed in a box-like shape and hollow inside.
- the tank 100 mainly has a bottom surface 101 , a top surface 102 opposed to the bottom surface 101 , and side surfaces 103 substantially orthogonal to the bottom surface 101 and the top surface 102 .
- An opening 102 a is formed in the top surface 102 .
- a mounting plate 104 for mounting the return filter 1 is provided on an upper side (+z-side) of the top surface 102 .
- a through-hole 104 a (see FIG. 2 ) is formed in the mounting plate 104 .
- the return filter 1 is inserted into an inside of the tank 100 from the opening 102 a and the through-hole 104 a.
- the opening 102 a and the through-hole 104 a are covered with a lid body 30 (described in detail later) of the return filter 1 .
- the mounting plate 104 is not necessarily required.
- the tank 100 includes the mounting plate 104 .
- An inflow portion 40 (see FIG. 2 . FIG. 1 omits the illustration) that causes the hydraulic oil to flow into the inside of the return filter 1 is inserted through the side surface 103 .
- the inflow portion 40 introduces the hydraulic oil from an outside of the tank 100 to the return filter 1 .
- the hydraulic oil introduced into the return filter 1 is filtered by the return filter 1 and stored in the tank 100 .
- An outflow port (not illustrated) that causes the hydraulic oil in the tank 100 to flow out to, for example, a hydraulic pump (not illustrated) is formed in the vicinity of the bottom surface 101 .
- a suction strainer 9 is provided inside the tank 100 . The hydraulic oil that has passed through the suction strainer 9 flows out from the outflow port to the outside of the tank 100 .
- a partition plate 105 is provided inside the tank 100 such that the hydraulic oil that has flown out from the return filter 1 does not directly contact the suction strainer 9 . Note that the partition plate 105 is not necessarily required.
- FIG. 2 is a cross-sectional view illustrating an overview of the return filter 1 .
- hatching for indicating a cross section is omitted.
- the return filter 1 mainly includes a case 10 , a filter element 20 , the lid body 30 , the inflow portion 40 , and an outflow portion 50 .
- the case 10 is formed of a material having high corrosion resistance (e.g., metal such as stainless steel).
- the case 10 is provided inside the tank 100 so as to protrude from the top surface 102 of the tank 100 to a lower side (-z-side) (see FIG. 1 ).
- the case 10 has a bottomed substantially tubular shape and has an open upper end surface.
- the case 10 is hollow inside and internally includes, for example, the filter element 20 .
- the case 10 has a bottom surface 11 .
- the outflow portion 50 is provided so as to penetrate the bottom surface 11 .
- the outflow portion 50 communicates between a space inside the filter element 20 and a space outside the case 10 .
- a mounting member 12 is provided in the vicinity of an upper end of the case 10 .
- the case 10 is provided in the tank 100 (here, to the mounting plate 104 ) via the mounting member 12 . Furthermore, the mounting member 12 integrates the case 10 and a flange portion 31 (described in detail later).
- the case 10 has two tubular portions 13 and 14 with different diameters.
- the tubular portion 14 has the diameter smaller than the diameter of the tubular portion 13 .
- the tubular portion 14 is provided on a lower side of the tubular portion 13 .
- the inflow portion 40 is provided for the tubular portion 13 .
- the inflow portion 40 communicates between a space inside the case 10 and outside the filter element 20 (space S 1 ) and a space outside the case 10 and inside the tank 100 (space S 3 , see FIG. 1 ).
- An inflow of the hydraulic oil from the inflow portion 40 stores the hydraulic oil in the case 10 .
- the filter element 20 is a member having a bottomed substantially tubular shape and provided inside the case 10 .
- the filter element 20 mainly includes a filter medium 21 , an outer tube portion 22 , an inner tube 23 , a plate 24 , and a plate 25 .
- the outer tube portion 22 , the inner tube 23 , and the plate 24 are integrated with the filter medium 21 .
- FIG. 3 is a cross-sectional view illustrating an overview of the filter element 20 .
- hatching for indicating a cross section is omitted.
- the filter medium 21 is a member having a substantially cylindrical shape and having openings at both ends.
- the filter medium 21 is formed by pleating a filter paper using, for example, synthetic resin or a paper, and connecting both ends of the pleated filter paper to form a cylindrical shape.
- the inner tube 23 where holes through which the hydraulic oil passes are formed in a substantially entire area is provided inside the filter medium 21 .
- the outer tube portion 22 is provided on an end on a lower side of the filter medium 21 and outside the filter medium 21 .
- the outer tube portion 22 mainly includes a plate-like portion 22 a having a substantially circular plate shape provided along a lower end surface of the filter medium 21 , and tubular portions 22 b and 22 c outside the filter medium 21 provided substantially parallel to the filter medium 21 .
- the plate-like portion 22 a is a substantially circular plate-shaped member having the central portion thicker than its peripheral edge portion, and has a hole 22 e having a substantially columnar shape in the center.
- the outflow portion 50 is inserted into the hole 22 e.
- the hole 22 e and the outflow portion 50 are sealed by a sealing member (for example, an O-ring) 61 .
- the tubular portion 22 b has a height substantially the same as a height of the filter medium 21 .
- the tubular portion 22 c has a height lower than that of the filter medium 21 and abuts on an outer circumferential surface of the tubular portion 22 b.
- the tubular portion 22 b and the tubular portion 22 c are integrated.
- a clearance is provided between the tubular portion 22 b and the filter medium 21 . This clearance serves as a dust pocket D (described in detail later). Note that although it is only necessary that the tubular portion 22 b does not abut on the filter medium 21 , as illustrated, the clearance of approximately half the thickness of the filter medium 21 is desirably present between the tubular portion 22 b and the filter medium 21 .
- the tubular portion 22 c abuts on the tubular portion 14 includes a case where a fine clearance is formed between the tubular portion 22 c and the tubular portion 14 so that the filter element 20 (tubular portion 22 c ) can move relative to the tubular portion 14 .
- the state where the hydraulic oil does not enter between the tubular portion 22 c and the tubular portion 14 is referred to as a state where “the tubular portion 22 c abuts on the tubular portion 14 .”
- a case where about 0.5 mm clearance is provided between the tubular portion 22 c and the tubular portion 14 is also included in the case where “the tubular portion 22 c abuts on the tubular portion 14 .”
- Holes 22 d through which the hydraulic oil passes are formed in a substantially entire area of a part of the tubular portion 22 b on which the tubular portion 22 c does not abuts. Meanwhile, the hole 22 d is not formed in a part on which the tubular portion 22 c abuts. Moreover, the hole 22 d is not formed in the tubular portion 22 c. In other words, the holes 22 d are formed in the substantially entire area of the part not abutting on the tubular portion 14 of the tubular portions 22 b and 22 c, and the hole 22 d is not formed in the part abutting on the tubular portion 14 of the tubular portions 22 b and 22 c.
- the hole 22 d may be formed in the substantially entire area of the tubular portion 22 b.
- the tubular portion 22 c covers an outside of the tubular portion 22 b, and therefore even when the holes 22 d are formed in the substantially entire area of the tubular portion 22 b, it can be said that the holes 22 d are not formed in the part abutting on the tubular portion 14 of the tubular portions 22 b and 22 c.
- the plate 24 is provided on an end on the upper side of the filter medium 21 .
- the plate 24 covers upper end surfaces of the filter medium 21 , the outer tube portion 22 , and the inner tube 23 .
- the plate 24 mainly includes a plate-like portion 24 a having a substantially circular plate shape provided along an upper end surface of the filter medium 21 , a tubular portion 24 b outside the tubular portion 22 b provided substantially parallel to the tubular portion 22 b, and a tubular portion 24 c provided on an inner peripheral edge of the plate-like portion 24 a.
- the tubular portion 24 b protrudes downward (in the ⁇ z direction) from the plate-like portion 24 a and abuts on the tubular portion 22 b.
- the tubular portion 24 c protrudes upward (in the +z direction) from the plate-like portion 24 a.
- the plate 25 is provided on a lower side of the tubular portion 24 c. Note that the plate 25 may be part of the plate 24 .
- the lid body 30 is provided outside the tank 100 (in the present embodiment, an upper side of the mounting plate 104 provided outside the tank 100 ).
- the lid body 30 is provided on the case 10 (here, the mounting member 12 ) and the plate 24 (here, the tubular portion 24 c ) so as to cover the opening of the upper end surface of the case 10 .
- the lid body 30 mainly includes the flange portion 31 , a cover 32 , and a mounting portion 33 .
- the flange portion 31 has a substantially cylindrical shape and is fixed to the case 10 (here, the mounting member 12 ).
- the cover 32 is a substantially plate-shaped member and provided on the upper side (+z-side) of the flange portion 31 so as to cover a hollow portion of the flange portion 31 .
- the cover 32 is detachably provided to the flange portion 31 .
- a hole 31 a is formed in the flange portion 31 , and an indicator 63 is attached to the hole 31 a.
- the indicator 63 detects a difference between a pressure inside the case 10 and a pressure outside the case.
- the mounting portion 33 is provided on the cover 32 .
- the mounting portion 33 is a substantially tubular member, and protrudes to the lower side ( ⁇ z-side) of the cover 32 .
- a valve 64 is provided on a lower side of the mounting portion 33 .
- the valve 64 is provided on the cover 32 via the mounting portion 33 .
- the valve 64 is usually closed.
- the valve 64 opens to flow the hydraulic oil from the space (space S 1 ) inside the case 10 and outside the filter element 20 to the space inside the filter element 20 and to obviate damage to the return filter 1 .
- the valve 64 is already well known, and thus, the description is omitted.
- the mounting portion 33 is inserted into the tubular portion 24 c, and the valve 64 is inserted into a hollow portion (space S 2 ) of the filter element 20 .
- the mounting portion 33 and the tubular portion 24 c are sealed by a sealing member (for example, an O-ring) 62 .
- Holes 33 a and 33 b that penetrate in a thickness direction (z direction) are formed in the mounting portion 33 .
- the hole 33 a and a hole 32 a formed in the cover 32 communicate between the internal space of the filter element 20 and the hole 31 a. This allows the indicator 63 to measure the pressure in the internal space of the filter element 20 .
- the hole 33 b, a hole 32 b formed in the cover 32 , a hole 31 b formed in the flange portion 31 , a hole 104 b formed in the mounting plate 104 , and a hole 102 b formed in the top surface 102 are connected to constitute a flow path 35 for air and hydraulic oil.
- the flow path 35 has a substantially U shape as a whole and has both ends opening to a surface on a lower side of the lid body 30 .
- the flow path 35 communicates between the space S 2 and the space S 3 .
- the dash-dotted line arrows in FIG. 2 indicate a flow of the hydraulic oil.
- the hydraulic oil starts flowing the inside of the hydraulic circuit.
- the hydraulic oil flows into the space S 1 and the inside of the case 10 is filled with the hydraulic oil.
- the inside of the case 10 spaces S 1 and S 2
- the initial air passes through the flow path 35 and is discharged to the space S 3 .
- the hydraulic oil flowing into the space S 1 flows from the outside to the inside of the filter medium 21 , and the filter medium 21 removes, for example, dust in the hydraulic oil.
- the hydraulic oil after filtration flows out to the space S 2 .
- the hydraulic oil after filtration flows out from the outflow portion 50 to the space S 3 .
- the hydraulic oil after filtration that has not flown out from the outflow portion 50 flows out to the space S 3 via the flow path 35 .
- the filter element 20 Since the repeated filtration clogs the filter medium 21 , the filter element 20 is replaced. To replace the filter element 20 , the work machine is stopped first. As the work machine stops, the hydraulic oil ceases to flow into the space S 1 , and thus the oil surface in the case 10 lowers. In the process, the dust captured by the filter medium 21 falls in the ⁇ z direction and remains in the dust pocket D between the filter medium 21 and the tubular portion 22 c.
- the flow path is formed in the lid body 30 . Therefore, the air passes through the flow path 35 and flows from the space S 3 into the spaces S 1 and S 2 , thus gradually lowering the oil surface even without removing the cover 32 from the flange portion 31 (synonymous with the case 10 ). Accordingly, when a certain amount of period (for example, approximately five minutes) has passed after the work machine stops, the air passes through the flow path 35 and flows into the inside of the case 10 , and thus the oil surface lowers with respect to the bottom surface 11 without removing the cover 32 from the flange portion 31 (case 10 ).
- a certain amount of period for example, approximately five minutes
- the hydraulic oil stored in the case 10 is all discharged to the tank 100 . Because the dust does not pass through the filter medium 21 , the dust remains in the dust pocket D and the hydraulic oil after filtration passes through the filter medium 21 . In addition, because the tubular portion 22 c abuts on the tubular portion 14 , the hydraulic oil prior to filtration does not remain between the tubular portion 22 c and the tubular portion 14 .
- the filter element 20 can be extracted from the open end on the upper portion of the case 10 .
- the hole 22 d is not formed in the tubular portion 22 c, so the dust removed by the filter medium 21 remains in the dust pocket D.
- the dust removed by the filter medium 21 does not escape to the outside of the filter element 20 .
- the hydraulic oil is all discharged from the case 10 , and the oil surface is lower than the bottom surface (here, the plate-like portion 22 a )of the filter element 20 . Therefore, the filter element 20 is not immersed in the hydraulic oil, and the used filter element 20 from which the oil is drained is extracted. As a result, a drip of the hydraulic oil to the outside of the return filter 1 can be avoided.
- the tubular portion 22 c abuts on the tubular portion 14 , this allows avoiding the dust contained in the liquid before filtration to flow out to the outside while the filter element is replaced.
- the formation of the flow path 35 in the cover 32 allows draining off the oil of the filter element 20 before removing the cover 32 .
- the drip of the hydraulic oil to the outside of the return filter 1 (causing an oil drip) during the replacement can be obviated.
- FIGS. 4A and 4B are perspective views of a main part illustrating an overview of a conventional return filter 110 , FIG. 4A illustrates its state during use, and FIG. 4B illustrates a state while a filter element is replaced.
- the return filter 110 is provided inside a tank that stores hydraulic oil.
- a range in which the hydraulic oil is present is indicated by shading.
- the hydraulic oil is fully contained in a case 111 during use. However, because the flow path 35 is not formed in the return filter 110 , the oil does not flow out from the case 111 even when a work machine stops operating. As illustrated in FIG. 4B , although an oil surface lowers for the first time when a lid 112 is removed in a replacement work, the oil surface cannot be lowered with respect to a bottom surface of the case 111 . Furthermore, even in the state where the oil surface lowers, a lower portion of the filter element 20 is immersed in the hydraulic oil prior to filtration. Thus, when a filter element 113 is pulled up, the hydraulic oil before filtration is mixed in an inside of the tank.
- the hydraulic oil can be discharged from the case 10 prior to the replacement work, so the oil of the filter element 20 can be drained off prior to the replacement work, and therefore the oil drip can be obviated.
- FIGS. 5A and 5B are drawings illustrating modifications of an outer tube portion
- FIG. 5A is a partially enlarged view of an outer tube portion 22 A according to Modification Example 1
- FIG. 5B is a partially enlarged view of an outer tube portion 22 B according to Modification Example 2.
- a tubular portion 22 b - 1 may be integrated with an upper side of the tubular portion 22 c by, for example, welding and may configure a diameter of the tubular portion 22 c and a diameter of the tubular portion 22 b to be substantially the same.
- a projection may be provided in a tubular portion 22 c - 1 , and a claw at a distal end of a tubular portion 22 b - 2 may be fitted to the projection of the tubular portion 22 c - 1 to integrate the tubular portion 22 c - 1 with the tubular portion 22 b - 1 .
- the tubular portions 22 c and 22 c - 1 abut on the tubular portion 14 .
- the flow path 35 communicates between the space S 2 and the space S 3
- the flow path 35 only needs to communicate between the internal space of the case 10 and the external space of the case 10 .
- a flow path that communicates between the space S 2 and the external space of the tank 100 may be provided in the lid body 30 .
- the air can pass through the flow path and be flown into the inside of the case 10 while the work machine stops.
- a valve is desirably provided in the flow path so that the hydraulic oil inside the case 10 does not flow out to the outside of the tank 100 .
- the flange portion 31 is provided with the indicator 63
- various sensors other than the indicator 63 can be attached to the flange portion 31 .
- providing a temperature sensor in the flange portion 31 allows measuring a temperature inside the space S 2 .
- the second embodiment of the present invention has a configuration in which an outflow portion includes a back pressure valve.
- FIG. 6 and FIG. 7 are cross-sectional views illustrating an overview of the return filter 2 .
- hatching for indicating a cross section is omitted.
- the return filter 2 mainly includes the case 10 , the filter element 20 , the lid body 30 , the inflow portion 40 (illustration is omitted), and an outflow portion 50 A.
- the outflow portion 50 A mainly includes a cylindrical portion 51 having a substantially bottomed cylindrical shape and a back pressure valve 52 .
- the cylindrical portion 51 has the substantially bottomed cylindrical shape as a whole, and includes a first cylindrical portion 51 a, a second cylindrical portion 51 b, and a bottom surface 51 c.
- the second cylindrical portion 51 b is provided on a lower side of the first cylindrical portion 51 a.
- An outflow hole 51 d is formed in the first cylindrical portion 51 a
- an outflow hole 51 e is formed in the second cylindrical portion 51 b.
- the outflow holes 51 d and 51 e are formed on side surfaces of the first cylindrical portion 51 a and the second cylindrical portion 51 b so as to penetrate the first cylindrical portion 51 a and the second cylindrical portion 51 b, respectively.
- the back pressure valve 52 is provided inside the cylindrical portion 51 .
- the back pressure valve 52 mainly includes a substantially plate-shaped valve body 52 a, an elastic member 52 b provided between the bottom surface 51 c of the cylindrical portion 51 and the valve body 52 a, and a valve seat 52 c provided on the cylindrical portion 51 .
- the valve seat 52 c is provided between the first cylindrical portion 51 a and the second cylindrical portion 51 b.
- FIG. 6 illustrates a closed state of the back pressure valve 52 in which the valve body 52 a abuts on the valve seat 52 c.
- FIG. 7 illustrates an open state of the back pressure valve 52 in which the valve body 52 a does not abut on the valve seat 52 c.
- the valve body 52 a moves against a biasing force from the elastic member 52 b, from the closed state to the open state.
- the back pressure valve 52 is in the closed state. In the closed state, while the space S 2 communicates with the space S 3 via the outflow hole 51 d, the space S 2 does not communicate with the space S 3 via the outflow hole 51 e.
- a flow rate of the hydraulic of is small, substantially 40 L (liters)/minute.
- the hydraulic oil flows into the inside of the case 10 from the inflow portion, the oil surface rises up to a position of an oil surface L indicated by the long-dotted line, the hydraulic oil is filtered by the filter medium 21 , and the hydraulic oil after filtration flows out from the outflow hole 51 .
- the back pressure valve 52 is in the closed state as illustrated in FIG. 6 .
- the flow rate of the hydraulic oil is large, and the flow rate increases up to substantially 1000 L (liters)/minute.
- the inside of the case 10 is filled with the hydraulic oil, and the pressure inside the case 10 becomes sufficiently high.
- the hydraulic oil pushes down the valve body 52 a against the biasing force from the elastic member 52 b, and the space S 2 communicates with the space S 3 via the outflow hole 51 e.
- the space S 2 communicates with the space S 3 via the outflow hole 51 d in the open state as well.
- the hydraulic oil after filtration flows out from the outflow hole 51 d and flows out from the outflow hole 51 e.
- the back pressure valve 52 is closed, and the air inside the case 10 is discharged to the outside of the case 10 through the flow path 35 . Accordingly, the air inside the return filter 2 can be purged so that no bubbles are generated in the hydraulic oil.
- the back pressure valve 52 when the flow rate of the hydraulic oil is small, the air does not flow from the flow path 35 into the inside of the case 10 , thus ensuring stable driving.
- the third embodiment of the present invention is a configuration in which an outflow portion and a flow path include check valves.
- a return filter 3 according to the third embodiment will be described below. Note that the same components as those in the first embodiment and the second embodiment are denoted by the same reference numerals, and descriptions thereof will be omitted.
- FIG. 8 is a cross-sectional view illustrating an overview of the return filter 3 .
- the return filter 3 mainly includes the case 10 , the filter element 20 , a lid body 30 A, the inflow portion 40 (illustration is omitted), and an outflow portion 50 B.
- the lid body 30 A mainly includes the flange portion 31 , the cover 32 , and a mounting portion 33 A.
- the mounting portion 33 A is a substantially tubular-shaped member, and protrudes to the lower side ( ⁇ z-side) of the cover 32 .
- the valve 64 is provided on a lower side of the mounting portion 33 A. Furthermore, a hole 33 c is formed in the mounting portion 33 A.
- the hole 33 c, the hole 32 b, the hole 31 b, the hole 104 b ( FIG. 8 omits the illustration), and the hole 102 b ( FIG. 8 omits the illustration) constitute a flow path 35 A for air and hydraulic oil.
- a check valve 65 is provided inside the flow path 35 A.
- FIG. 9 is a cross-sectional view illustrating an overview of the check valve 65 .
- hatching for indicating a cross section is partly omitted.
- the check valve 65 mainly includes a rod-like member 651 and a moving member 652 .
- the rod-like member 651 has a substantially tubular shape and covers both ends.
- the rod-like member 651 is provided substantially along the flow path 35 A (here, the hole 33 c ).
- the rod-like member 651 has two holes 651 a and 651 b on its side surface.
- the moving member 652 is a member having a substantially cylindrical shape, and has a tubular hole 652 a into which the rod-like member 651 is inserted. By sliding the tubular hole 652 a along the rod-like member 651 , the moving member 652 moves along the rod-like member 651 .
- the hole 33 c has a hole 33 d having a substantially cylindrical shape and a hole 33 e having an inner diameter larger than that of the hole 33 .
- the moving member 652 is provided inside the hole 33 e.
- FIG. 10 is a cross-sectional view taken along the line B-B in FIG. 9 .
- the hole 33 e has four projections 33 f that regulate the movement of the moving member 652 . Distal ends of the projections 33 f abut on an outer circumferential surface of the moving member 652 .
- the hole 33 e has four recessed portions 33 g serving as flow paths.
- the moving member 652 When the moving member 652 is pushed up by the hydraulic oil, the moving member 652 moves in the +z direction and rises until it abuts on the cover 32 . At this time, the moving member 652 covers the hole 651 a (does not cover the hole 651 b ) and the hydraulic oil does not flow into the internal space of the rod-like member 651 , namely, the flow path 35 A.
- the check valve 65 inside the flow path 35 A in this manner, only the air can be discharged via the flow path 35 A and the hydraulic oil is not discharged via the flow path 35 A.
- the outflow portion 50 B mainly includes a cylindrical portion 51 A having a substantially bottomed cylindrical shape, a back pressure valve 52 A, and the check valve 53 .
- the cylindrical portion 51 A has a substantially bottomed cylindrical shape as a whole, and includes a first cylindrical portion 51 h having a substantially cylindrical shape, a second cylindrical portion 51 i having a substantially cylindrical shape, and a bottom surface 51 j.
- the second cylindrical portion 51 i is provided on a lower side of the first cylindrical portion 51 h.
- the bottom surface 51 j obstructs a bottom surface of the second cylindrical portion 51 i.
- An outflow hole 51 k is formed in the second cylindrical portion 51 i.
- the outflow hole 51 k is formed in a side surface of the second cylindrical portion 51 i so as to penetrate the second cylindrical portion 51 i.
- the back pressure valve 52 A is provided inside the second cylindrical portion 51 i.
- the back pressure valve 52 A mainly includes a substantially plate-shaped valve body 52 d, the elastic member 52 b provided between the bottom surface 51 j of the cylindrical portion 51 A and the valve body 52 d, and a valve seat 52 e provided on the cylindrical portion 51 A.
- the valve seat 52 e is provided between the first cylindrical portion 51 h and the second cylindrical portion 51 i.
- valve body 52 d moves against a biasing force from the elastic member 52 b, from the closed state in which the valve body 52 d abuts on the valve seat 52 e (the state illustrated in FIG. 8 ) to the open state in which the valve body 52 d does not abut on the valve seat 52 e.
- the check valve 53 mainly includes a tubular case 531 , an upper end member 532 , a moving member 533 , and a tube-shaped portion 534 .
- the tube-shaped portion 534 is a tube that connects the cylindrical portion 51 A and the tubular case 531 , and has one end provided on the first cylindrical portion 51 h and the other end provided on the tubular case 531 .
- the tubular case 531 , the upper end member 532 , and the tube-shaped portion 534 constitute a valve case.
- the moving member 533 is provided inside the valve case.
- FIGS. 11A and 11B are drawings illustrating an overview of the check valve 53 , FIG. 11A is its vertical cross-sectional view, and FIG. 11B is a cross-sectional view taken along the line A-A in FIG. 11A .
- hatching for indicating a cross section is partly omitted.
- the tubular case 531 is a member having a substantially cylindrical shape, and internally has a hole 531 a serving as a flow path.
- the tube-shaped portion 534 communicates between the hole 531 a and a space inside the first cylindrical portion 51 h.
- the central axis of the hole 531 a is substantially identical to the vertical direction.
- the upper end member 532 is a member attached to an upper end of the tubular case 531 .
- a hole 532 a serving as a flow path is formed inside the upper end member 532 .
- a female screw portion 531 b is formed in the vicinity of an upper end of the hole 531 a, and a male screw portion 532 b of the upper end member 532 is screwed into the female screw portion 531 b.
- the hole 531 a communicates with the hole 532 a.
- the upper end member 532 has a lower end surface as a valve seat 532 c.
- the valve seat 532 c is provided on an upper end side of the valve case.
- the moving member 533 is a member having a substantially cylindrical shape and provided inside the hole 531 a. As illustrated in FIG. 11B , the hole 531 a has four projections 531 e that regulate the movement of the moving member 533 . Distal ends of the projections 531 e abut on an outer circumferential surface of the moving member 533 .
- the hole 531 a has four recessed portions 531 d serving as flow paths.
- the moving member 533 is movable inside the hole 531 a in the z direction.
- the moving member 533 while the moving member 533 is not pushed up by the hydraulic oil, the moving member 533 abuts on a positioning portion 531 c formed in the hole 531 a.
- the positioning portion 531 c is provided on a lower end side of the valve case.
- the air inside the case 10 can be avoided to be discharged from the outflow portion 50 B. Consequently, it is possible to avoid bubbles to be generated in the hydraulic oil stored in the tank 100 .
- the bubbles When bubbles are contained in the hydraulic oil stored in the tank 100 , the bubbles pass through the suction strainer 9 (see FIG. 1 ) and flow into the pump to generate an erosion, possibly shortening a lifespan of the pump.
- the air in the case 10 is discharged via the flow path 35 A particularly when the flow rate of the hydraulic oil is small, so, for example, the occurrence of erosion can be reduced.
- the back pressure valve 52 and the check valve 65 by providing the back pressure valve 52 and the check valve 65 , the backflow of the hydraulic oil inside the case 10 to the tank 100 via the flow path 35 A during the operation of the engine can be reduced.
- providing the check valve 53 avoids the hydraulic oil to flow out from the check valve 53 when the flow rate of the hydraulic oil increases, and this makes it possible to reduce the generation of bubbles in the hydraulic oil.
- FIGS. 12A and 12B are drawings illustrating an overview of a check valve 53 A according to a modification, FIG. 12A is its vertical cross-sectional view, and FIG. 12B is a cross-sectional view taken along the line C-C in FIG. 12A .
- FIGS. 12A and 12B hatching for indicating a cross section is partly omitted.
- the check valve 53 A mainly includes the tubular case 531 , an upper end member 532 A, a moving member 533 A, the tube-shaped portion 534 (illustration is omitted), and an elastic member 535 .
- the tubular case 531 , the upper end member 532 A attached to an upper end of the tubular case 531 , and the tube-shaped portion 534 constitute a valve case.
- One end of the elastic member 535 is provided on the upper end member 532 A.
- the other end of the elastic member 535 is provided on the moving member 533 A.
- the elastic member 535 biases a force in the ⁇ z direction to the moving member 533 A.
- changing the biasing force given by the elastic member 535 facilitates adjustment of the flow rate to open and close the check valve 53 A.
- the fourth embodiment of the present invention is a configuration in which a tubular portion is provided inside the inner tube 23 .
- FIG. 13 is a cross-sectional view illustrating an overview of the return filter 4 .
- hatching for indicating a cross section is omitted.
- the return filter 4 mainly includes a case 10 A, the filter element 20 , the lid body 30 , the inflow portion 40 (illustration is omitted), and the outflow portion 50 B (illustration is omitted except for the cylindrical portion 51 A).
- the case 10 A mainly includes a bottom surface 11 A, the mounting member 12 , and tubular portions 13 and 14 A.
- the tubular portion 14 A includes a tubular portion 14 a provided outside the bottom surface 11 A, and a tubular portion 14 b provided inside the bottom surface 11 A.
- the tubular portion 14 a and the tubular portion 14 b are provided substantially in parallel.
- the tubular portion 14 a is provided on a lower side of the tubular portion 13 and has a diameter smaller than a diameter of the tubular portion 13 .
- the tubular portion 14 b is provided inside the filter element 20 (inner tube 23 ) and has a diameter smaller than a diameter of the inner tube 23 .
- the tubular portion 14 b has a height lower than heights of the filter medium 21 and the inner tube 23 .
- a lower end of the tubular portion 14 b is positioned downward with respect to lower ends of the filter medium 21 and the inner tube 23 .
- Drain holes 14 c are provided in a position in the vicinity of the lower end of the tubular portion 14 b, that is, adjacent to the plate-like portion 22 a of the tubular portion 14 b.
- the dash-dotted line arrows in FIG. 13 indicate a flow of the hydraulic oil.
- the hydraulic oil flowing into the space S 1 flows from the outside to the inside of the filter medium 21 , and the filter medium 21 removes, for example, dust in the hydraulic oil.
- the hydraulic oil after filtration flows out to the space S 2 .
- the hydraulic oil flows into the spaces S 1 and S 2 so that the initial air is discharged via the flow path 35 . Because the tubular portion 14 b is provided inside the inner tube 23 , the initial air easily flows upward and the initial air can be effectively removed.
- the tubular portion 14 b is provided inside the inner tube 23 , when the hydraulic oil flowing into the space S 1 flows into the space S 2 , the hydraulic oil flows upward (in the +z direction) and is guided to the upper portion of the filter medium 21 . As a result, a filtration area of the filter medium 21 can be effectively used.
- the hydraulic oil flows out via the check valve 53 .
- the drain holes 14 c are provided in the vicinity of the lower end of the tubular portion 14 b, the hydraulic oil present outside the tubular portion 14 b flows out to the space S 2 via the drain holes 14 c. Furthermore, the air flows from the space S 3 into the spaces S 1 and S 2 through the flow path 35 . Thus, the oil surface in the case 10 A gradually lowers.
- the hydraulic oil easily flows upward by the tubular portion 14 b, so the filtration area of the filter medium 21 can be effectively used.
- the air easily flows upward by the tubular portion 14 b, the initial air can be effectively removed.
- tubular portion 14 b is integrated with the bottom surface 11 A
- the tubular portion 14 b and the bottom surface 11 A may be separate members.
- the bottom surface 11 A and the tubular portion 14 b may be separate members, and the tubular portion 14 b may be inserted from a lower side of the case 10 A to join the bottom surface 11 A and the tubular portion 14 b together.
- FIG. 14 is a cross-sectional view illustrating an overview of a return filter 4 A according to a modification.
- hatching for indicating a cross section is omitted. Note that the same components as those in the first to third embodiments are denoted by the same reference numerals, and descriptions thereof will be omitted.
- the return filter 4 A mainly includes the case 10 , a filter element 20 A, the lid body 30 , the inflow portion 40 (illustration is omitted), and the outflow portion 50 B (illustration is omitted except for the cylindrical portion 51 A).
- the filter element 20 A mainly includes the filter medium 21 , an outer tube portion 22 C, the inner tube 23 , the plate 24 , and a tubular portion 26 .
- the outer tube portion 22 C mainly includes a plate-like portion 22 f having a substantially circular plate shape provided along a lower end surface of the filter medium 21 , and tubular portions 22 b and 22 c outside the filter medium 21 provided substantially parallel to the filter medium 21 .
- the plate-like portion 22 f is a substantially circular plate-shaped member having the central portion thicker than its peripheral edge portion. A difference between the plate-like portion 22 f and the plate-like portion 22 a is only diameters of outer circumferential surfaces of the central portions.
- the plate-like portion 22 f is integrated with the filter medium 21 and the tubular portion 26 . In other words, a lower end of the tubular portion 26 is positioned at substantially the same height as the lower ends of the filter medium 21 and the inner tube 23 .
- the tubular portion 26 is provided inside the inner tube 23 and has a diameter smaller than the diameter of the inner tube 23 .
- the tubular portion 26 has a height lower than the heights of the filter medium 21 and the inner tube 23 .
- Drain holes 26 a are provided in a position in the vicinity of the lower end of the tubular portion 26 , that is, adjacent to the plate-like portion 22 f of the tubular portion 26 .
- the tubular portion 26 is provided inside the inner tube 23 , when the hydraulic oil flowing into the space S 1 flows into the space S 2 , the hydraulic oil flows upward (in the +z direction) and is guided to the upper portion of the filter medium 21 . As a result, the filtration area of the filter medium 21 can be effectively used. In addition, since the air easily flows upward by the tubular portion 26 , the initial air can be effectively removed. Furthermore, because the drain holes 26 a are provided, while the work machine stops, the hydraulic oil present outside the tubular portion 26 can be discharged via the drain holes 26 a, and the oil surface in the case 10 can be lowered.
- the return filter 4 or 4 A includes the outflow portion 50 B, the outflow portion 50 B is not essential.
- the return filter 4 or 4 A may include the outflow portion 50 or may include the outflow portion 50 A.
- the term “substantially” is not to be understood as merely being strictly the same, and is a concept that includes errors and modifications to an extent that does not result in loss in identity.
- the “substantially cylindrical shape” is a concept that includes a case where, for example, the shape can be placed in the same category as the cylindrical shape, and is not strictly limited to the cylindrical shape.
- simple expressions such as orthogonal, parallel, and identical are not to be understood as merely being strictly, for example, orthogonal, parallel, and identical, and include being, for example, substantially parallel, substantially orthogonal, and substantially identical.
- the term “vicinity” means to include a range of regions (which can be determined as desired) near a position serving as a reference.
- a vicinity of an end refers to a range of regions vicinity the end, and is a concept indicating that the end may or needs not be included.
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Filtration Of Liquid (AREA)
- Fluid-Pressure Circuits (AREA)
- Supply Devices, Intensifiers, Converters, And Telemotors (AREA)
Abstract
Description
- This application is a continuation application of International Patent Application No. PCT/JP2018/041935 filed on Nov. 13, 2018, which claims priority to Japanese Patent Applications No. 2017-222304 filed on Nov. 17, 2017, No. 2017-223198 filed on Nov. 20, 2017, and No. 2018-152458 filed on Aug. 13, 2018, the entire contents of which are incorporated by reference.
- The present invention relates to a filter device.
-
Patent Document 1 discloses a filter device installed to an oil tank. In this filter device, hydraulic oil before being filtered flows from a flow path in a hydraulic circulation circuit to the filter device, the hydraulic oil is filtered through a filter element, and the hydraulic oil after filtration flows from the filter device into the oil tank. - Patent Document 1: JP 2006-046142 A
- In the cited in
Patent Document 1, the filter element is provided inside a housing, and an opening in an upper end of the housing is covered with a lid member. In the citedPatent Document 1, the lid member is removed from the housing to replace the filter element via the opening. However, in the citedPatent Document 1, when the used filter element is taken out from the housing, the hydraulic oil before filtration remains inside the housing or the filter element. This possibly causes the hydraulic oil and dust before filtration to flow out to the oil tank. - One or more embodiments of the present invention is to provide a filter device that allows avoiding liquid and dust before filtration to flow out to a tank during replacement of a filter element.
- A filter device according to one or more embodiments of the present invention, for example, includes a case, a filter element, a lid body, an inflow portion, and an outflow portion. The case has a substantially bottomed tubular shape with an open upper end. The filter element having a substantially cylindrical shape is provided inside the case. The filter element includes a filter medium having a substantially cylindrical shape, an outer tube portion, and an upper plate. The outer tube portion includes a plate-like (plate-shaped) portion and a tubular portion. The plate-shaped portion has a substantially circular plate shape and is provided along a lower end surface of the filter medium. The tubular portion is provided outside the filter medium to be substantially parallel to the filter medium. The upper plate has a part with a substantially circular plate shape and is provided so as to cover upper end surfaces of the filter medium and the outer tube portion. The lid body is provided on the case and the upper plate so as to cover an upper end of the case. The inflow portion communicates between a space inside the case and outside the filter element and a space outside the case. The outflow portion communicates between a space inside the filter element and the space outside the case. The outflow portion is provided so as to penetrate a bottom surface of the case. The case includes a first tubular portion and a second tubular portion provided on a lower side of the first tubular portion. The second tubular portion has a diameter smaller than a diameter of the first tubular portion. The inflow portion is provided in the first tubular portion. In a state where the filter element is provided inside the case, the plate-shaped portion abuts on the bottom surface of the case and the tubular portion abuts on the second tubular portion. A part abutting on the second tubular portion of the tubular portion is absent of a hole. A part without abutment on the second tubular portion of the tubular portion has a plurality of holes.
- According to the filter device according to one or more embodiments of the present invention, the case includes the first tubular portion and the second tubular portion positioned with the lower side of the first tubular portion. The second tubular portion has the diameter smaller than that of the first tubular portion. In the state where the filter element is provided inside the case, the tubular portion of the filter element abuts on the second tubular portion. The part abutting on the second tubular portion of the tubular portion is absent of the hole. The part without abutment on the second tubular portion of the tubular portion has the plurality of holes. Therefore, filtered dust accumulates between the filter medium and the tubular portion. Moreover, liquid before filtration does not accumulate between the filter element and the case. This allows avoiding the liquid and the dust before filtration to flow out to a tank during replacement of the filter element.
- Here, the lid body may have a first hole that communicates between a space inside the case and the space outside the case. Accordingly, air flows into the inside of the case through the first hole, thus ensuring discharging the liquid from the case and gradually lowering an oil surface without removing the lid body from the case. As a result, when the filter element is replaced, oil is drained from the filter element, and therefore a drip of the liquid to an outside of the filter device can be avoided.
- Here, the filter device may be configured as follows. The case is provided inside a tank. The lid body is provided on an upper side of the tank. The first hole has a substantially U shape and has both ends opening to a surface on a lower side of the lid body. The first hole communicates between the space inside the filter element and a space outside the case and inside the tank. Accordingly, after a certain amount of period (for example, approximately five minutes) has passed after a work machine where the tank is provided stops, all of the liquid stored in the case can be discharged to the tank. Furthermore, the hydraulic oil after filtration that has not flown out from the outflow portion can be flown out to a tank via the first hole.
- Here, the outer tube portion may be integrated with the filter medium so as to provide a clearance between the tubular portion and the filter medium. Thus, the space for accumulating the dust can be sufficiently ensured between the tubular portion and the filter medium.
- Here, the filter device may be configured as follows. The lid body includes a flange portion and a cover. The flange portion having a substantially cylindrical shape is fixed to the case. The cover is detachably provided so as to cover a hollow portion of the flange portion. A sensor is attached to the flange portion. This eliminates the need for removing the sensor during replacement of the filter element, and maintenance can be facilitated.
- Here, the filter device may be configured as follows. The filter element includes an inner tube provided inside the filter medium. The case or the filter element includes a tubular member provided inside the filter medium. The tubular member has a lower end positioned at substantially a same height as a lower end of the filter medium or a lower side with respect to the lower end of the filter medium. The tubular member has a diameter smaller than a diameter of the inner tube. The tubular member has a height lower than heights of the inner tube and the filter medium. This causes the hydraulic oil to flow upward along the tubular member and is guided to an upper portion of the filter medium. As a result, a filtration area of the filter medium can be effectively used. In addition, since the air easily flows upward along the tubular member, initial air can be effectively removed.
- Here, the tubular member may have a drain hole adjacent to the plate-shaped portion. Accordingly, while a work machine stops, the hydraulic oil present outside the tubular portion can be discharged via the drain hole, and the oil surface in the case can be lowered.
- One or more embodiments of the present invention allows avoiding the liquid and the dust before filtration to flow out to the tank during replacement of the filter element.
-
FIG. 1 is a perspective view of a main part illustrating an overview of atank 100 in which areturn filter 1 according to one embodiment of the present invention is provided. -
FIG. 2 is a cross-sectional view illustrating an overview of thereturn filter 1. -
FIG. 3 is a cross-sectional view illustrating an overview of afilter element 20. -
FIGS. 4A and 4B are perspective views of a main part illustrating an overview of aconventional return filter 110,FIG. 4A illustrates its state during use, andFIG. 4B illustrates a state while a filter element is replaced. -
FIGS. 5A and 5B are drawings illustrating modifications of an outer tube portion,FIG. 5A is a partially enlarged view of anouter tube portion 22A according to Modification Example 1, andFIG. 5B is a partially enlarged view of anouter tube portion 22B according to Modification Example 2. -
FIG. 6 is a cross-sectional view illustrating an overview of areturn filter 2. -
FIG. 7 is a cross-sectional view illustrating an overview of thereturn filter 2. -
FIG. 8 is a cross-sectional view illustrating an overview of areturn filter 3. -
FIG. 9 is a cross-sectional view illustrating an overview of acheck valve 65. -
FIG. 10 is a cross-sectional view taken along the line B-B inFIG. 9 . -
FIGS. 11A and 11B are drawings illustrating an overview of acheck valve 53,FIG. 11A is its vertical cross-sectional view, andFIG. 11B is a cross-sectional view taken along the line A-A inFIG. 11A . -
FIGS. 12A and 12B are drawings illustrating an overview of acheck valve 53A,FIG. 12A is its vertical cross-sectional view, andFIG. 12B is a cross-sectional view taken along the line C-C inFIG. 12A . -
FIG. 13 is a cross-sectional view illustrating an overview of areturn filter 4. -
FIG. 14 is a cross-sectional view illustrating an overview of areturn filter 4A. - Hereinafter, with reference to the drawings, detailed description will be made on embodiments of the present invention. In the present embodiment, while hydraulic oil is described as an example of liquid to be filtered, the liquid to be filtered is not limited to the hydraulic oil. Also, while the following embodiments are described with an example of a return filter, a filter device of the present invention is not limited to the return filter.
-
FIG. 1 is a cross-sectional view illustrating an overview of atank 100 in which areturn filter 1 according to one embodiment of the present invention is provided. InFIG. 1 , hatching for indicating a cross section is omitted. - The
tank 100 is a tank for storing hydraulic oil. Thetank 100 is installed in the work machine (not illustrated) (e.g., a hydraulic device), and is provided in a hydraulic circuit of hydraulic oil supplied to the hydraulic device. However, thetank 100 is not limited to one provided in the hydraulic circuit. - The
tank 100 is, for example, formed in a box-like shape and hollow inside. Thetank 100 mainly has abottom surface 101, atop surface 102 opposed to thebottom surface 101, andside surfaces 103 substantially orthogonal to thebottom surface 101 and thetop surface 102. Anopening 102 a (seeFIG. 2 ) is formed in thetop surface 102. - A mounting
plate 104 for mounting thereturn filter 1 is provided on an upper side (+z-side) of thetop surface 102. A through-hole 104 a (seeFIG. 2 ) is formed in the mountingplate 104. Thereturn filter 1 is inserted into an inside of thetank 100 from the opening 102 a and the through-hole 104 a. The opening 102 a and the through-hole 104 a are covered with a lid body 30 (described in detail later) of thereturn filter 1. - Note that the mounting
plate 104 is not necessarily required. For example, when a thickness of thetop surface 102 of thetank 100 is thickened such that thetop surface 102 meets the functionality of the mountingplate 104, the mountingplate 104 is unnecessary. In the present invention, thetank 100 includes the mountingplate 104. - An inflow portion 40 (see
FIG. 2 .FIG. 1 omits the illustration) that causes the hydraulic oil to flow into the inside of thereturn filter 1 is inserted through theside surface 103. Theinflow portion 40 introduces the hydraulic oil from an outside of thetank 100 to thereturn filter 1. The hydraulic oil introduced into thereturn filter 1 is filtered by thereturn filter 1 and stored in thetank 100. - An outflow port (not illustrated) that causes the hydraulic oil in the
tank 100 to flow out to, for example, a hydraulic pump (not illustrated) is formed in the vicinity of thebottom surface 101. Asuction strainer 9 is provided inside thetank 100. The hydraulic oil that has passed through thesuction strainer 9 flows out from the outflow port to the outside of thetank 100. - A
partition plate 105 is provided inside thetank 100 such that the hydraulic oil that has flown out from thereturn filter 1 does not directly contact thesuction strainer 9. Note that thepartition plate 105 is not necessarily required. - Next, the
return filter 1 will be described.FIG. 2 is a cross-sectional view illustrating an overview of thereturn filter 1. InFIG. 2 , hatching for indicating a cross section is omitted. - The
return filter 1 mainly includes acase 10, afilter element 20, thelid body 30, theinflow portion 40, and anoutflow portion 50. - The
case 10 is formed of a material having high corrosion resistance (e.g., metal such as stainless steel). Thecase 10 is provided inside thetank 100 so as to protrude from thetop surface 102 of thetank 100 to a lower side (-z-side) (seeFIG. 1 ). - The
case 10 has a bottomed substantially tubular shape and has an open upper end surface. Thecase 10 is hollow inside and internally includes, for example, thefilter element 20. - The
case 10 has abottom surface 11. Theoutflow portion 50 is provided so as to penetrate thebottom surface 11. Theoutflow portion 50 communicates between a space inside thefilter element 20 and a space outside thecase 10. - A mounting
member 12 is provided in the vicinity of an upper end of thecase 10. Thecase 10 is provided in the tank 100 (here, to the mounting plate 104) via the mountingmember 12. Furthermore, the mountingmember 12 integrates thecase 10 and a flange portion 31 (described in detail later). - The
case 10 has twotubular portions tubular portion 14 has the diameter smaller than the diameter of thetubular portion 13. Thetubular portion 14 is provided on a lower side of thetubular portion 13. - The
inflow portion 40 is provided for thetubular portion 13. Theinflow portion 40 communicates between a space inside thecase 10 and outside the filter element 20 (space S1) and a space outside thecase 10 and inside the tank 100 (space S3, seeFIG. 1 ). An inflow of the hydraulic oil from theinflow portion 40 stores the hydraulic oil in thecase 10. - The
filter element 20 is a member having a bottomed substantially tubular shape and provided inside thecase 10. Thefilter element 20 mainly includes afilter medium 21, anouter tube portion 22, aninner tube 23, aplate 24, and aplate 25. Theouter tube portion 22, theinner tube 23, and theplate 24 are integrated with thefilter medium 21. -
FIG. 3 is a cross-sectional view illustrating an overview of thefilter element 20. InFIG. 3 , hatching for indicating a cross section is omitted. Thefilter medium 21 is a member having a substantially cylindrical shape and having openings at both ends. Thefilter medium 21 is formed by pleating a filter paper using, for example, synthetic resin or a paper, and connecting both ends of the pleated filter paper to form a cylindrical shape. Theinner tube 23 where holes through which the hydraulic oil passes are formed in a substantially entire area is provided inside thefilter medium 21. - The
outer tube portion 22 is provided on an end on a lower side of thefilter medium 21 and outside thefilter medium 21. Theouter tube portion 22 mainly includes a plate-like portion 22 a having a substantially circular plate shape provided along a lower end surface of thefilter medium 21, andtubular portions filter medium 21 provided substantially parallel to thefilter medium 21. - The plate-
like portion 22 a is a substantially circular plate-shaped member having the central portion thicker than its peripheral edge portion, and has ahole 22 e having a substantially columnar shape in the center. Theoutflow portion 50 is inserted into thehole 22 e. Thehole 22 e and theoutflow portion 50 are sealed by a sealing member (for example, an O-ring) 61. - The
tubular portion 22 b has a height substantially the same as a height of thefilter medium 21. Thetubular portion 22 c has a height lower than that of thefilter medium 21 and abuts on an outer circumferential surface of thetubular portion 22 b. Thetubular portion 22 b and thetubular portion 22 c are integrated. A clearance is provided between thetubular portion 22 b and thefilter medium 21. This clearance serves as a dust pocket D (described in detail later). Note that although it is only necessary that thetubular portion 22 b does not abut on thefilter medium 21, as illustrated, the clearance of approximately half the thickness of thefilter medium 21 is desirably present between thetubular portion 22 b and thefilter medium 21. - As illustrated in
FIG. 2 , in a state where thefilter element 20 is provided inside thecase 10, the plate-like portion 22 a abuts on abottom surface 11, and thetubular portion 22 c abuts on thetubular portion 14. As a result, the hydraulic oil does not flow into between the filter element 20 (tubular portion 22 c) and thetubular portion 14. - Note that “the
tubular portion 22 c abuts on thetubular portion 14” described here includes a case where a fine clearance is formed between thetubular portion 22 c and thetubular portion 14 so that the filter element 20 (tubular portion 22 c) can move relative to thetubular portion 14. In other words, the state where the hydraulic oil does not enter between thetubular portion 22 c and thetubular portion 14 is referred to as a state where “thetubular portion 22 c abuts on thetubular portion 14.” For example, a case where about 0.5 mm clearance is provided between thetubular portion 22 c and thetubular portion 14 is also included in the case where “thetubular portion 22 c abuts on thetubular portion 14.” -
Holes 22 d through which the hydraulic oil passes are formed in a substantially entire area of a part of thetubular portion 22 b on which thetubular portion 22 c does not abuts. Meanwhile, thehole 22 d is not formed in a part on which thetubular portion 22 c abuts. Moreover, thehole 22 d is not formed in thetubular portion 22 c. In other words, theholes 22 d are formed in the substantially entire area of the part not abutting on thetubular portion 14 of thetubular portions hole 22 d is not formed in the part abutting on thetubular portion 14 of thetubular portions - Note that in the present embodiment, while the
hole 22 d is not formed in the part abutting on thetubular portion 14 of thetubular portion 22 b, thehole 22 d may be formed in the substantially entire area of thetubular portion 22 b. Thetubular portion 22 c covers an outside of thetubular portion 22 b, and therefore even when theholes 22 d are formed in the substantially entire area of thetubular portion 22 b, it can be said that theholes 22 d are not formed in the part abutting on thetubular portion 14 of thetubular portions - The description will now return to
FIG. 3 . Theplate 24 is provided on an end on the upper side of thefilter medium 21. Theplate 24 covers upper end surfaces of thefilter medium 21, theouter tube portion 22, and theinner tube 23. - The
plate 24 mainly includes a plate-like portion 24 a having a substantially circular plate shape provided along an upper end surface of thefilter medium 21, atubular portion 24 b outside thetubular portion 22 b provided substantially parallel to thetubular portion 22 b, and atubular portion 24 c provided on an inner peripheral edge of the plate-like portion 24 a. Thetubular portion 24 b protrudes downward (in the −z direction) from the plate-like portion 24 a and abuts on thetubular portion 22 b. Thetubular portion 24 c protrudes upward (in the +z direction) from the plate-like portion 24 a. Theplate 25 is provided on a lower side of thetubular portion 24 c. Note that theplate 25 may be part of theplate 24. - The description will now return to
FIG. 2 . Thelid body 30 is provided outside the tank 100 (in the present embodiment, an upper side of the mountingplate 104 provided outside the tank 100). Thelid body 30 is provided on the case 10 (here, the mounting member 12) and the plate 24 (here, thetubular portion 24 c ) so as to cover the opening of the upper end surface of thecase 10. - The
lid body 30 mainly includes theflange portion 31, acover 32, and a mountingportion 33. Theflange portion 31 has a substantially cylindrical shape and is fixed to the case 10 (here, the mounting member 12). Thecover 32 is a substantially plate-shaped member and provided on the upper side (+z-side) of theflange portion 31 so as to cover a hollow portion of theflange portion 31. Thecover 32 is detachably provided to theflange portion 31. - A
hole 31 a is formed in theflange portion 31, and anindicator 63 is attached to thehole 31 a. Theindicator 63 detects a difference between a pressure inside thecase 10 and a pressure outside the case. By providing theindicator 63 on theflange portion 31, theindicator 63 remains attached to thecase 10 side when thefilter element 20 is replaced, and therefore maintenance is easy. - The mounting
portion 33 is provided on thecover 32. The mountingportion 33 is a substantially tubular member, and protrudes to the lower side (−z-side) of thecover 32. Avalve 64 is provided on a lower side of the mountingportion 33. In other words, thevalve 64 is provided on thecover 32 via the mountingportion 33. As illustrated inFIG. 2 , thevalve 64 is usually closed. When thefilter medium 21 becomes clogged and the pressure inside thecase 10 increases, thevalve 64 opens to flow the hydraulic oil from the space (space S1) inside thecase 10 and outside thefilter element 20 to the space inside thefilter element 20 and to obviate damage to thereturn filter 1. Thevalve 64 is already well known, and thus, the description is omitted. - The mounting
portion 33 is inserted into thetubular portion 24 c, and thevalve 64 is inserted into a hollow portion (space S2) of thefilter element 20. The mountingportion 33 and thetubular portion 24 c are sealed by a sealing member (for example, an O-ring) 62.Holes portion 33. - The
hole 33 a and ahole 32 a formed in thecover 32 communicate between the internal space of thefilter element 20 and thehole 31 a. This allows theindicator 63 to measure the pressure in the internal space of thefilter element 20. - The
hole 33 b, ahole 32 b formed in thecover 32, ahole 31 b formed in theflange portion 31, ahole 104 b formed in the mountingplate 104, and ahole 102 b formed in thetop surface 102 are connected to constitute aflow path 35 for air and hydraulic oil. Theflow path 35 has a substantially U shape as a whole and has both ends opening to a surface on a lower side of thelid body 30. Theflow path 35 communicates between the space S2 and the space S3. - Next, the functionality of the
return filter 1 thus configured will be described. The dash-dotted line arrows inFIG. 2 indicate a flow of the hydraulic oil. - For example, when the work machine starts driving, the hydraulic oil starts flowing the inside of the hydraulic circuit. In association with this, the hydraulic oil flows into the space S1 and the inside of the
case 10 is filled with the hydraulic oil. Because the inside of the case 10 (spaces S1 and S2) is filled with initial air, as a position of an oil surface in thecase 10 rises (moves in the +z direction), the initial air passes through theflow path 35 and is discharged to the space S3. - The hydraulic oil flowing into the space S1 flows from the outside to the inside of the
filter medium 21, and thefilter medium 21 removes, for example, dust in the hydraulic oil. The hydraulic oil after filtration flows out to the space S2. After that, the hydraulic oil after filtration flows out from theoutflow portion 50 to the space S3. Furthermore, the hydraulic oil after filtration that has not flown out from theoutflow portion 50 flows out to the space S3 via theflow path 35. - Since the repeated filtration clogs the
filter medium 21, thefilter element 20 is replaced. To replace thefilter element 20, the work machine is stopped first. As the work machine stops, the hydraulic oil ceases to flow into the space S1, and thus the oil surface in thecase 10 lowers. In the process, the dust captured by thefilter medium 21 falls in the −z direction and remains in the dust pocket D between thefilter medium 21 and thetubular portion 22 c. - Here, the flow path is formed in the
lid body 30. Therefore, the air passes through theflow path 35 and flows from the space S3 into the spaces S1 and S2, thus gradually lowering the oil surface even without removing thecover 32 from the flange portion 31 (synonymous with the case 10). Accordingly, when a certain amount of period (for example, approximately five minutes) has passed after the work machine stops, the air passes through theflow path 35 and flows into the inside of thecase 10, and thus the oil surface lowers with respect to thebottom surface 11 without removing thecover 32 from the flange portion 31 (case 10). - In this way, the hydraulic oil stored in the
case 10 is all discharged to thetank 100. Because the dust does not pass through thefilter medium 21, the dust remains in the dust pocket D and the hydraulic oil after filtration passes through thefilter medium 21. In addition, because thetubular portion 22 c abuts on thetubular portion 14, the hydraulic oil prior to filtration does not remain between thetubular portion 22 c and thetubular portion 14. - When the
cover 32 of thelid body 30 is removed from theflange portion 31, thefilter element 20 can be extracted from the open end on the upper portion of thecase 10. Thehole 22 d is not formed in thetubular portion 22 c, so the dust removed by thefilter medium 21 remains in the dust pocket D. Thus, when the usedfilter element 20 is extracted, the dust removed by thefilter medium 21 does not escape to the outside of thefilter element 20. - Furthermore, after a certain amount of period has passed after the work machine stops, the hydraulic oil is all discharged from the
case 10, and the oil surface is lower than the bottom surface (here, the plate-like portion 22 a)of thefilter element 20. Therefore, thefilter element 20 is not immersed in the hydraulic oil, and the usedfilter element 20 from which the oil is drained is extracted. As a result, a drip of the hydraulic oil to the outside of thereturn filter 1 can be avoided. - According to the present embodiment, the
tubular portion 22 c abuts on thetubular portion 14, this allows avoiding the dust contained in the liquid before filtration to flow out to the outside while the filter element is replaced. In addition, the formation of theflow path 35 in thecover 32 allows draining off the oil of thefilter element 20 before removing thecover 32. Thus, the drip of the hydraulic oil to the outside of the return filter 1 (causing an oil drip) during the replacement can be obviated. - A known return filter is now described for comparison with the present invention.
FIGS. 4A and 4B are perspective views of a main part illustrating an overview of aconventional return filter 110,FIG. 4A illustrates its state during use, andFIG. 4B illustrates a state while a filter element is replaced. Thereturn filter 110 is provided inside a tank that stores hydraulic oil. InFIGS. 4A and 4B , a range in which the hydraulic oil is present is indicated by shading. - As illustrated in
FIG. 4A , the hydraulic oil is fully contained in acase 111 during use. However, because theflow path 35 is not formed in thereturn filter 110, the oil does not flow out from thecase 111 even when a work machine stops operating. As illustrated inFIG. 4B , although an oil surface lowers for the first time when alid 112 is removed in a replacement work, the oil surface cannot be lowered with respect to a bottom surface of thecase 111. Furthermore, even in the state where the oil surface lowers, a lower portion of thefilter element 20 is immersed in the hydraulic oil prior to filtration. Thus, when afilter element 113 is pulled up, the hydraulic oil before filtration is mixed in an inside of the tank. - In contrast, in the present embodiment, the hydraulic oil can be discharged from the
case 10 prior to the replacement work, so the oil of thefilter element 20 can be drained off prior to the replacement work, and therefore the oil drip can be obviated. - Note that in the present embodiment, while the outside of the
tubular portion 22 b is covered with thetubular portion 22 c to provide the dust pocket D in thefilter element 20, the configuration of thetubular portions FIGS. 5A and 5B are drawings illustrating modifications of an outer tube portion,FIG. 5A is a partially enlarged view of anouter tube portion 22A according to Modification Example 1, andFIG. 5B is a partially enlarged view of anouter tube portion 22B according to Modification Example 2. - As in the
outer tube portion 22A illustrated inFIG. 5A , atubular portion 22 b-1 may be integrated with an upper side of thetubular portion 22 c by, for example, welding and may configure a diameter of thetubular portion 22 c and a diameter of thetubular portion 22 b to be substantially the same. In addition, as in theouter tube portion 22B illustrated inFIG. 5B , a projection may be provided in atubular portion 22 c-1, and a claw at a distal end of atubular portion 22 b-2 may be fitted to the projection of thetubular portion 22 c-1 to integrate thetubular portion 22 c-1 with thetubular portion 22 b-1. In the case of theouter tube portions tubular portions tubular portion 14. - Note that while in the present embodiment, the
flow path 35 communicates between the space S2 and the space S3, theflow path 35 only needs to communicate between the internal space of thecase 10 and the external space of thecase 10. For Example, a flow path that communicates between the space S2 and the external space of thetank 100 may be provided in thelid body 30. In this case as well, the air can pass through the flow path and be flown into the inside of thecase 10 while the work machine stops. However, when the flow path communicates between the space S2 and the external space of thetank 100, for example, a valve is desirably provided in the flow path so that the hydraulic oil inside thecase 10 does not flow out to the outside of thetank 100. - While in the present embodiment, the
flange portion 31 is provided with theindicator 63, various sensors other than theindicator 63 can be attached to theflange portion 31. For example, providing a temperature sensor in theflange portion 31 allows measuring a temperature inside the space S2. - The second embodiment of the present invention has a configuration in which an outflow portion includes a back pressure valve. Below, description is given of a
return filter 2 according to the second embodiment. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and descriptions thereof will be omitted. -
FIG. 6 andFIG. 7 are cross-sectional views illustrating an overview of thereturn filter 2. InFIG. 6 andFIG. 7 , hatching for indicating a cross section is omitted. Thereturn filter 2 mainly includes thecase 10, thefilter element 20, thelid body 30, the inflow portion 40 (illustration is omitted), and anoutflow portion 50A. - The
outflow portion 50A mainly includes acylindrical portion 51 having a substantially bottomed cylindrical shape and aback pressure valve 52. - The
cylindrical portion 51 has the substantially bottomed cylindrical shape as a whole, and includes a firstcylindrical portion 51 a, a secondcylindrical portion 51 b, and abottom surface 51 c. The secondcylindrical portion 51 b is provided on a lower side of the firstcylindrical portion 51 a. Anoutflow hole 51 d is formed in the firstcylindrical portion 51 a, and anoutflow hole 51 e is formed in the secondcylindrical portion 51 b. The outflow holes 51 d and 51 e are formed on side surfaces of the firstcylindrical portion 51 a and the secondcylindrical portion 51 b so as to penetrate the firstcylindrical portion 51 a and the secondcylindrical portion 51 b, respectively. - The
back pressure valve 52 is provided inside thecylindrical portion 51. Theback pressure valve 52 mainly includes a substantially plate-shapedvalve body 52 a, anelastic member 52 b provided between thebottom surface 51 c of thecylindrical portion 51 and thevalve body 52 a, and avalve seat 52 c provided on thecylindrical portion 51. Thevalve seat 52 c is provided between the firstcylindrical portion 51 a and the secondcylindrical portion 51 b. - Next, the functionality of the
return filter 2 thus configured will be described.FIG. 6 illustrates a closed state of theback pressure valve 52 in which thevalve body 52 a abuts on thevalve seat 52 c.FIG. 7 illustrates an open state of theback pressure valve 52 in which thevalve body 52 a does not abut on thevalve seat 52 c. As the pressure inside thecase 10 rises, thevalve body 52 a moves against a biasing force from theelastic member 52 b, from the closed state to the open state. - When the operation of the internal combustion engine (engine) of the work machine stops, the hydraulic oil is not contained in the
case 10. Thus, as illustrated inFIG. 6 , theback pressure valve 52 is in the closed state. In the closed state, while the space S2 communicates with the space S3 via theoutflow hole 51 d, the space S2 does not communicate with the space S3 via theoutflow hole 51 e. - While the engine is idling, a flow rate of the hydraulic of is small, substantially 40 L (liters)/minute. In this case, the hydraulic oil flows into the inside of the
case 10 from the inflow portion, the oil surface rises up to a position of an oil surface L indicated by the long-dotted line, the hydraulic oil is filtered by thefilter medium 21, and the hydraulic oil after filtration flows out from theoutflow hole 51 . However, because the flow rate of the hydraulic oil is small and the pressure inside thecase 10 is not sufficiently high, theback pressure valve 52 is in the closed state as illustrated inFIG. 6 . - In contrast, while the engine of the work machine is operating, the flow rate of the hydraulic oil is large, and the flow rate increases up to substantially 1000 L (liters)/minute. In this case, the inside of the
case 10 is filled with the hydraulic oil, and the pressure inside thecase 10 becomes sufficiently high. Thus, as illustrated inFIG. 7 , the hydraulic oil pushes down thevalve body 52 a against the biasing force from theelastic member 52 b, and the space S2 communicates with the space S3 via theoutflow hole 51 e. Similar to the closed state, the space S2 communicates with the space S3 via theoutflow hole 51 d in the open state as well. As a result, the hydraulic oil after filtration flows out from theoutflow hole 51 d and flows out from theoutflow hole 51 e. - After that, when the engine of the work machine stops, the flow rate of the hydraulic oil decreases and the
back pressure valve 52 closes. Furthermore, the hydraulic oil in thecase 10 flows out from theoutflow hole 51 d, and the oil surface in thecase 10 lowers. Thus, when a certain amount of period has passed after the work machine stops, the air flows into the inside of thecase 10 through theflow path 35, thereby lowering the oil surface with respect to thebottom surface 11 without removing thecover 32 from the flange portion 31 (case 10). Thus, extracting the usedfilter element 20 in the oil drained state allows obviating the oil drip. - According to this embodiment, while the engine is idling, the flow rate of the hydraulic oil is small, the
back pressure valve 52 is closed, and the air inside thecase 10 is discharged to the outside of thecase 10 through theflow path 35. Accordingly, the air inside thereturn filter 2 can be purged so that no bubbles are generated in the hydraulic oil. In addition, by providing theback pressure valve 52, when the flow rate of the hydraulic oil is small, the air does not flow from theflow path 35 into the inside of thecase 10, thus ensuring stable driving. - The third embodiment of the present invention is a configuration in which an outflow portion and a flow path include check valves. A
return filter 3 according to the third embodiment will be described below. Note that the same components as those in the first embodiment and the second embodiment are denoted by the same reference numerals, and descriptions thereof will be omitted. -
FIG. 8 is a cross-sectional view illustrating an overview of thereturn filter 3. InFIG. 8 , hatching for indicating a cross section is omitted. Thereturn filter 3 mainly includes thecase 10, thefilter element 20, alid body 30A, the inflow portion 40 (illustration is omitted), and anoutflow portion 50B. - The
lid body 30A mainly includes theflange portion 31, thecover 32, and a mountingportion 33A. The mountingportion 33A is a substantially tubular-shaped member, and protrudes to the lower side (−z-side) of thecover 32. Thevalve 64 is provided on a lower side of the mountingportion 33A. Furthermore, ahole 33 c is formed in the mountingportion 33A. - The
hole 33 c, thehole 32 b, thehole 31 b, thehole 104 b (FIG. 8 omits the illustration), and thehole 102 b (FIG. 8 omits the illustration) constitute aflow path 35A for air and hydraulic oil. Acheck valve 65 is provided inside theflow path 35A. -
FIG. 9 is a cross-sectional view illustrating an overview of thecheck valve 65. InFIG. 9 , hatching for indicating a cross section is partly omitted. Thecheck valve 65 mainly includes a rod-like member 651 and a movingmember 652. - The rod-
like member 651 has a substantially tubular shape and covers both ends. The rod-like member 651 is provided substantially along theflow path 35A (here, thehole 33 c). The rod-like member 651 has twoholes - The moving
member 652 is a member having a substantially cylindrical shape, and has atubular hole 652 a into which the rod-like member 651 is inserted. By sliding thetubular hole 652 a along the rod-like member 651, the movingmember 652 moves along the rod-like member 651. - The
hole 33 c has ahole 33 d having a substantially cylindrical shape and ahole 33 e having an inner diameter larger than that of thehole 33 . The movingmember 652 is provided inside thehole 33 e.FIG. 10 is a cross-sectional view taken along the line B-B inFIG. 9 . Thehole 33 e has fourprojections 33 f that regulate the movement of the movingmember 652. Distal ends of theprojections 33 f abut on an outer circumferential surface of the movingmember 652. Thehole 33 e has four recessedportions 33 g serving as flow paths. - The description will now return to
FIG. 9 . In a usual time during which the movingmember 652 is not pushed up by the hydraulic oil (the state illustrated inFIG. 9 ), the movingmember 652 abuts on apositioning portion 33 h formed in thehole 33 c and does not cover thehole 651 a or thehole 651 b. Thus, as illustrated by the dashed line inFIG. 9 , the air flows from thehole 33 d to thehole 32 b via the internal space of the rod-like member 651. - When the moving
member 652 is pushed up by the hydraulic oil, the movingmember 652 moves in the +z direction and rises until it abuts on thecover 32. At this time, the movingmember 652 covers thehole 651 a (does not cover thehole 651 b) and the hydraulic oil does not flow into the internal space of the rod-like member 651, namely, theflow path 35A. By providing thecheck valve 65 inside theflow path 35A in this manner, only the air can be discharged via theflow path 35A and the hydraulic oil is not discharged via theflow path 35A. - The description will now return to
FIG. 8 . Theoutflow portion 50B mainly includes acylindrical portion 51A having a substantially bottomed cylindrical shape, a back pressure valve 52A, and thecheck valve 53. - The
cylindrical portion 51A has a substantially bottomed cylindrical shape as a whole, and includes a firstcylindrical portion 51 h having a substantially cylindrical shape, a secondcylindrical portion 51 i having a substantially cylindrical shape, and abottom surface 51 j. The secondcylindrical portion 51 i is provided on a lower side of the firstcylindrical portion 51 h. Thebottom surface 51 j obstructs a bottom surface of the secondcylindrical portion 51 i. Anoutflow hole 51 k is formed in the secondcylindrical portion 51 i. Theoutflow hole 51 k is formed in a side surface of the secondcylindrical portion 51 i so as to penetrate the secondcylindrical portion 51 i. - The back pressure valve 52A is provided inside the second
cylindrical portion 51 i. The back pressure valve 52A mainly includes a substantially plate-shaped valve body 52 d, theelastic member 52 b provided between thebottom surface 51 j of thecylindrical portion 51A and the valve body 52 d, and avalve seat 52 e provided on thecylindrical portion 51A. Thevalve seat 52 e is provided between the firstcylindrical portion 51 h and the secondcylindrical portion 51 i. - As the pressure inside the
case 10 rises, the valve body 52 d moves against a biasing force from theelastic member 52 b, from the closed state in which the valve body 52 d abuts on thevalve seat 52 e (the state illustrated inFIG. 8 ) to the open state in which the valve body 52 d does not abut on thevalve seat 52 e. - When the operation of the engine of the work machine stops, the hydraulic oil is not contained in the
case 10. Thus, the back pressure valve 52A is in the closed state and the space S2 does not communicate with the space S3 (seeFIG. 1 ). - When the engine of the work machine operates and the flow rate of the hydraulic oil increases, the inside of the
case 10 is filled with the hydraulic oil, and the pressure inside thecase 10 becomes sufficiently high. Thus, the hydraulic oil pushes down the valve body 52 d against the biasing force from theelastic member 52 b, and the back pressure valve 52A enters the open state. As a result, the space S2 communicates with the space S3 via theoutflow hole 51 k, and the hydraulic oil after filtration flows out from theoutflow hole 51 k. - While the back pressure valve 52A enters the open state from the closed state, the hydraulic oil gradually flows into the inside of the
case 10, and therefore, the air that has filled the inside of thecase 10 is pushed out of thecase 10. While the air is primarily discharged from theflow path 35A, a part of the air is discharged from thecheck valve 53. - The
check valve 53 mainly includes atubular case 531, anupper end member 532, a movingmember 533, and a tube-shapedportion 534. The tube-shapedportion 534 is a tube that connects thecylindrical portion 51A and thetubular case 531, and has one end provided on the firstcylindrical portion 51 h and the other end provided on thetubular case 531. Thetubular case 531, theupper end member 532, and the tube-shapedportion 534 constitute a valve case. The movingmember 533 is provided inside the valve case. -
FIGS. 11A and 11B are drawings illustrating an overview of thecheck valve 53,FIG. 11A is its vertical cross-sectional view, andFIG. 11B is a cross-sectional view taken along the line A-A inFIG. 11A . InFIGS. 11A and 11B , hatching for indicating a cross section is partly omitted. Thetubular case 531 is a member having a substantially cylindrical shape, and internally has ahole 531 a serving as a flow path. The tube-shapedportion 534 communicates between thehole 531 a and a space inside the firstcylindrical portion 51 h. The central axis of thehole 531 a is substantially identical to the vertical direction. - The
upper end member 532 is a member attached to an upper end of thetubular case 531. Ahole 532 a serving as a flow path is formed inside theupper end member 532. Afemale screw portion 531 b is formed in the vicinity of an upper end of thehole 531 a, and amale screw portion 532 b of theupper end member 532 is screwed into thefemale screw portion 531 b. When theupper end member 532 is screwed onto thetubular case 531, thehole 531 a communicates with thehole 532 a. - The
upper end member 532 has a lower end surface as avalve seat 532 c. Thevalve seat 532 c is provided on an upper end side of the valve case. - The moving
member 533 is a member having a substantially cylindrical shape and provided inside thehole 531 a. As illustrated inFIG. 11B , thehole 531 a has fourprojections 531 e that regulate the movement of the movingmember 533. Distal ends of theprojections 531 e abut on an outer circumferential surface of the movingmember 533. Thehole 531 a has four recessedportions 531 d serving as flow paths. Thus, the movingmember 533 is movable inside thehole 531 a in the z direction. - As illustrated in
FIG. 11A , while the movingmember 533 is not pushed up by the hydraulic oil, the movingmember 533 abuts on apositioning portion 531 c formed in thehole 531 a. Thepositioning portion 531 c is provided on a lower end side of the valve case. - While the moving
member 533 abuts on thepositioning portion 531 c, thecheck valve 53 is in the open state, and the air in thecase 10 is discharged to the space S3 through the check valve 53 (see the dashed line inFIG. 11A ). When the movingmember 533 is pushed up and moves upward in the vertical direction, the movingmember 533 abuts on thevalve seat 532 c (see the dotted line inFIG. 11A ). - Next, the functionality of the
return filter 3 thus configured will be described. When the operation of the internal combustion engine (engine) of the work machine stops, the hydraulic oil is not contained in thecase 10 and the back pressure valve 52A is in the closed state. In addition, thecheck valve 53 and thecheck valve 65 are in the open state. - When the engine of the work machine starts operating, since the flow rate of the hydraulic oil, that is, the hydraulic oil flowing the inside of the
cylindrical portion 51A, is small, the hydraulic oil cannot push up the movingmember 533. Thus, thecheck valve 53 is in the open state, and the air or the hydraulic oil flows to the space S3 via thecheck valve 53. - In contrast, an increase in the flow rate of the hydraulic oil rises the pressure inside the
case 10 and increases the hydraulic oil flowing the inside of thecylindrical portion 51A, and thus the hydraulic oil flows into thehole 531 a via the tube-shapedportion 534. As a result, the hydraulic oil pushes up the movingmember 533, and thecheck valve 53 is in the closed state. This obviates gushing of the oil from thecheck valve 53 when the engine is operated and causing generation of bubbles. Further, at substantially the same time when thecheck valve 53 enters the closed state, the hydraulic oil pushes up the movingmember 652, and thecheck valve 65 enters the closed state. This allows avoiding the hydraulic oil in thecase 10 to be discharged via theflow path 35A. - Note that, during idling (low flow rate), the initial air in the
case 10 is discharged to the space S3 through theflow path 35A, and therefore, the initial air is not discharged from thecase 10 after the flow rate of the hydraulic oil increases. - Also, as the flow rate of the hydraulic oil increases, the back pressure valve 52A opens. As a result, the hydraulic oil after filtration flows out from the
outflow hole 51 k. - After that, when the engine of the work machine stops, the flow rate of the hydraulic oil decreases and the back pressure valve 52A closes. When the engine of the work machine stops, the moving
member 533 moves in the −z direction by its own weight, and thecheck valve 53 enters the open state. As a result, the hydraulic oil in thecase 10 is discharged via thecheck valve 53. In addition, when the engine of the work machine stops, the movingmember 652 moves in the −z direction by its own weight, and thecheck valve 65 enters the open state. As a result, the air flows into the inside of thecase 10 through theflow path 35A. In this way, the oil surface lowers with respect to thebottom surface 11 when a certain amount of period has passed after the work machine stops. This allows the avoiding the oil to drip when thefilter element 20 is extracted. - According to the present embodiment, when the flow rate of the hydraulic oil increases, the air inside the
case 10 can be avoided to be discharged from theoutflow portion 50B. Consequently, it is possible to avoid bubbles to be generated in the hydraulic oil stored in thetank 100. - When bubbles are contained in the hydraulic oil stored in the
tank 100, the bubbles pass through the suction strainer 9 (seeFIG. 1 ) and flow into the pump to generate an erosion, possibly shortening a lifespan of the pump. In the present embodiment, the air in thecase 10 is discharged via theflow path 35A particularly when the flow rate of the hydraulic oil is small, so, for example, the occurrence of erosion can be reduced. - In addition, according to the present embodiment, by providing the
back pressure valve 52 and thecheck valve 65, the backflow of the hydraulic oil inside thecase 10 to thetank 100 via theflow path 35A during the operation of the engine can be reduced. In particular, providing thecheck valve 53 avoids the hydraulic oil to flow out from thecheck valve 53 when the flow rate of the hydraulic oil increases, and this makes it possible to reduce the generation of bubbles in the hydraulic oil. - Note that while in the present embodiment, the falling of the moving
member 533 by its own weight causes thecheck valve 53 to enter the open state from the closed state, the elastic member may assist the movement of the movingmember 533.FIGS. 12A and 12B are drawings illustrating an overview of acheck valve 53A according to a modification,FIG. 12A is its vertical cross-sectional view, andFIG. 12B is a cross-sectional view taken along the line C-C inFIG. 12A . InFIGS. 12A and 12B , hatching for indicating a cross section is partly omitted. - The
check valve 53A mainly includes thetubular case 531, anupper end member 532A, a movingmember 533A, the tube-shaped portion 534 (illustration is omitted), and anelastic member 535. - The
tubular case 531, theupper end member 532A attached to an upper end of thetubular case 531, and the tube-shapedportion 534 constitute a valve case. One end of theelastic member 535 is provided on theupper end member 532A. The other end of theelastic member 535 is provided on the movingmember 533A. Theelastic member 535 biases a force in the −z direction to the movingmember 533A. - When the hydraulic oil pushes up the moving
member 533A against the biasing force from theelastic member 535, thecheck valve 53A enters the closed state. When the flow rate of the hydraulic oil decreases, theelastic member 535 pushes down the movingmember 533A, thereby causing thecheck valve 53A to enter the open state. - According to this modification, changing the biasing force given by the elastic member 535 (for example, a spring constant of the elastic member 535) facilitates adjustment of the flow rate to open and close the
check valve 53A. - The fourth embodiment of the present invention is a configuration in which a tubular portion is provided inside the
inner tube 23. Below, a description is given of areturn filter 4 according to the fourth embodiment. Note that the same components as those in the first to third embodiments are denoted by the same reference numerals, and descriptions thereof will be omitted. -
FIG. 13 is a cross-sectional view illustrating an overview of thereturn filter 4. InFIG. 13 , hatching for indicating a cross section is omitted. Thereturn filter 4 mainly includes acase 10A, thefilter element 20, thelid body 30, the inflow portion 40 (illustration is omitted), and theoutflow portion 50B (illustration is omitted except for thecylindrical portion 51A). - The
case 10A mainly includes abottom surface 11A, the mountingmember 12, andtubular portions tubular portion 14A includes a tubular portion 14 a provided outside thebottom surface 11A, and a tubular portion 14 b provided inside thebottom surface 11A. The tubular portion 14 a and the tubular portion 14 b are provided substantially in parallel. - The tubular portion 14 a is provided on a lower side of the
tubular portion 13 and has a diameter smaller than a diameter of thetubular portion 13. The tubular portion 14 b is provided inside the filter element 20 (inner tube 23) and has a diameter smaller than a diameter of theinner tube 23. In addition, the tubular portion 14 b has a height lower than heights of thefilter medium 21 and theinner tube 23. A lower end of the tubular portion 14 b is positioned downward with respect to lower ends of thefilter medium 21 and theinner tube 23. - Drain holes 14 c are provided in a position in the vicinity of the lower end of the tubular portion 14 b, that is, adjacent to the plate-
like portion 22 a of the tubular portion 14 b. - Next, the functionality of the
return filter 4 thus configured will be described. The dash-dotted line arrows inFIG. 13 indicate a flow of the hydraulic oil. - For example, after the work machine starts driving, the hydraulic oil flowing into the space S1 flows from the outside to the inside of the
filter medium 21, and thefilter medium 21 removes, for example, dust in the hydraulic oil. The hydraulic oil after filtration flows out to the space S2. The hydraulic oil flows into the spaces S1 and S2 so that the initial air is discharged via theflow path 35. Because the tubular portion 14 b is provided inside theinner tube 23, the initial air easily flows upward and the initial air can be effectively removed. - In addition, because the tubular portion 14 b is provided inside the
inner tube 23, when the hydraulic oil flowing into the space S1 flows into the space S2, the hydraulic oil flows upward (in the +z direction) and is guided to the upper portion of thefilter medium 21. As a result, a filtration area of thefilter medium 21 can be effectively used. - When the work machine stops, the hydraulic oil flows out via the
check valve 53. In addition, because the drain holes 14 c are provided in the vicinity of the lower end of the tubular portion 14 b, the hydraulic oil present outside the tubular portion 14 b flows out to the space S2 via the drain holes 14 c. Furthermore, the air flows from the space S3 into the spaces S1 and S2 through theflow path 35. Thus, the oil surface in thecase 10A gradually lowers. - According to the present embodiment, the hydraulic oil easily flows upward by the tubular portion 14 b, so the filtration area of the
filter medium 21 can be effectively used. In addition, since the air easily flows upward by the tubular portion 14 b, the initial air can be effectively removed. - Note that while in the present embodiment, the tubular portion 14 b is integrated with the
bottom surface 11A, the tubular portion 14 b and thebottom surface 11A may be separate members. For example, thebottom surface 11A and the tubular portion 14 b may be separate members, and the tubular portion 14 b may be inserted from a lower side of thecase 10A to join thebottom surface 11A and the tubular portion 14 b together. - In addition, while in the present embodiment, the tubular portion 14 b provided on the
case 10A side is provided, the tubular portion may be provided on the filter element side.FIG. 14 is a cross-sectional view illustrating an overview of areturn filter 4A according to a modification. InFIG. 14 , hatching for indicating a cross section is omitted. Note that the same components as those in the first to third embodiments are denoted by the same reference numerals, and descriptions thereof will be omitted. - The
return filter 4A mainly includes thecase 10, afilter element 20A, thelid body 30, the inflow portion 40 (illustration is omitted), and theoutflow portion 50B (illustration is omitted except for thecylindrical portion 51A). Thefilter element 20A mainly includes thefilter medium 21, an outer tube portion 22C, theinner tube 23, theplate 24, and atubular portion 26. - The outer tube portion 22C mainly includes a plate-like portion 22 f having a substantially circular plate shape provided along a lower end surface of the
filter medium 21, andtubular portions filter medium 21 provided substantially parallel to thefilter medium 21. The plate-like portion 22 f is a substantially circular plate-shaped member having the central portion thicker than its peripheral edge portion. A difference between the plate-like portion 22 f and the plate-like portion 22 a is only diameters of outer circumferential surfaces of the central portions. The plate-like portion 22 f is integrated with thefilter medium 21 and thetubular portion 26. In other words, a lower end of thetubular portion 26 is positioned at substantially the same height as the lower ends of thefilter medium 21 and theinner tube 23. - The
tubular portion 26 is provided inside theinner tube 23 and has a diameter smaller than the diameter of theinner tube 23. In addition, thetubular portion 26 has a height lower than the heights of thefilter medium 21 and theinner tube 23. Drain holes 26 a are provided in a position in the vicinity of the lower end of thetubular portion 26, that is, adjacent to the plate-like portion 22 f of thetubular portion 26. - With the
return filter 4A, because thetubular portion 26 is provided inside theinner tube 23, when the hydraulic oil flowing into the space S1 flows into the space S2, the hydraulic oil flows upward (in the +z direction) and is guided to the upper portion of thefilter medium 21. As a result, the filtration area of thefilter medium 21 can be effectively used. In addition, since the air easily flows upward by thetubular portion 26, the initial air can be effectively removed. Furthermore, because the drain holes 26 a are provided, while the work machine stops, the hydraulic oil present outside thetubular portion 26 can be discharged via the drain holes 26 a, and the oil surface in thecase 10 can be lowered. - Note that while the
return filter outflow portion 50B, theoutflow portion 50B is not essential. Thereturn filter outflow portion 50 or may include theoutflow portion 50A. - The embodiments of the invention are described above in detail with reference to the drawings. Specific configurations are not limited to the embodiments and also include changes in the design or the like within a scope that does not depart from the gist of the invention. For example, the above examples have been explained in detail in order to facilitate understanding of the present invention and are not necessarily limited to examples provided with the entirety of the configuration described above. In addition, the configuration of an embodiment may be partially replaced with the configuration of a different embodiment, or the configuration of the different embodiment may be added to, deleted from, or replaced with the configuration of the embodiment.
- In addition, the term “substantially” is not to be understood as merely being strictly the same, and is a concept that includes errors and modifications to an extent that does not result in loss in identity. For example, the “substantially cylindrical shape” is a concept that includes a case where, for example, the shape can be placed in the same category as the cylindrical shape, and is not strictly limited to the cylindrical shape. Further, simple expressions such as orthogonal, parallel, and identical are not to be understood as merely being strictly, for example, orthogonal, parallel, and identical, and include being, for example, substantially parallel, substantially orthogonal, and substantially identical.
- In addition, the term “vicinity” means to include a range of regions (which can be determined as desired) near a position serving as a reference. For example, the term “a vicinity of an end” refers to a range of regions vicinity the end, and is a concept indicating that the end may or needs not be included.
-
- 1, 2, 3, 4, 4A Return filter
- 9 Suction strainer
- 10, 10A Case
- 11, 11A Bottom surface
- 12 Mounting member
- 13, 14, 14A Tubular portion
- 14 a, 14 b Tubular portion
- 14 c Drain hole
- 20, 20A Filter element
- 21 Filter medium
- 22, 22A, 22B, 22C Outer tube portion
- 22 a, 22 f Plate-like portion
- 22 b, 22 b-1, 22 b-2 Tubular portion
- 22 c, 22 c-1 Tubular portion
- 22 d, 22 e Hole
- 23 Inner tube
- 24, 25 Plate
- 24 a Plate-like portion
- 24 b, 24 c Tubular portion
- 26 Tubular portion
- 26 a Drain hole
- 30 Lid body
- 31 Flange portion
- 31 a Hole
- 31 b Hole
- 32 Cover
- 32 a, 32 b Hole
- 33, 33A Mounting portion
- 33 a, 33 b, 33 c, 33 d, 33 e Hole
- 33 f Protrusion
- 33 g Recessed portion
- 33 h Positioning portion
- 35, 35A Flow path
- 40 Inflow portion
- 50, 50A, 50B Outflow portion
- 51, 51A Cylindrical portion
- 51 a, 51 h First cylindrical portion
- 51 b, 51 i Second cylindrical portion
- 51 c Bottom surface
- 51 d, 51 e, 51 k Outflow hole
- 51 j Bottom surface
- 52, 52A Back pressure valve
- 52 a, 52 d Valve body
- 52 b Elastic member
- 52 c, 52 e Valve seat
- 53, 53A Check valve
- 61, 62 Sealing member
- 63 Indicator
- 64 Valve
- 65 Check valve
- 100 Tank
- 101 Bottom surface
- 102 Top surface
- 102 a Opening
- 102 b Hole
- 103 Side surface
- 104 Mounting plate
- 104 a Through-hole
- 104 b Hole
- 105 Partition plate
- 110 Return filter
- 111 Case
- 112 Lid
- 113 Filter element
- 531 Tubular case
- 531 a Hole
- 531 b Female screw portion
- 531 c Positioning portion
- 531 d Recessed portion
- 531 e Protrusion
- 532, 532A Upper end member
- 532 a Hole
- 532 b Male screw portion
- 532 c Valve seat
- 533, 533A Moving member
- 534 Tube-shaped portion
- 535 Elastic member
- 651 Rod-like member
- 651 a Hole
- 652 Moving member
- 652 a Tubular hole
- 651 b Hole
Claims (16)
Applications Claiming Priority (10)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2017222304 | 2017-11-17 | ||
JP2017-222304 | 2017-11-17 | ||
JPJP2017-222304 | 2017-11-17 | ||
JP2017-223198 | 2017-11-20 | ||
JPJP2017-223198 | 2017-11-20 | ||
JP2017223198 | 2017-11-20 | ||
JPJP2018-152458 | 2018-08-13 | ||
JP2018-152458 | 2018-08-13 | ||
JP2018152458 | 2018-08-13 | ||
PCT/JP2018/041935 WO2019098174A1 (en) | 2017-11-17 | 2018-11-13 | Filter device |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2018/041935 Continuation WO2019098174A1 (en) | 2017-11-17 | 2018-11-13 | Filter device |
Publications (2)
Publication Number | Publication Date |
---|---|
US20200230533A1 true US20200230533A1 (en) | 2020-07-23 |
US11052336B2 US11052336B2 (en) | 2021-07-06 |
Family
ID=66539516
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US16/840,507 Active 2039-07-03 US11541338B2 (en) | 2017-11-17 | 2020-04-06 | Filter device |
US16/840,511 Active US11052336B2 (en) | 2017-11-17 | 2020-04-06 | Filter device |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US16/840,507 Active 2039-07-03 US11541338B2 (en) | 2017-11-17 | 2020-04-06 | Filter device |
Country Status (6)
Country | Link |
---|---|
US (2) | US11541338B2 (en) |
EP (2) | EP3711837B1 (en) |
JP (2) | JP7219475B2 (en) |
KR (2) | KR102651725B1 (en) |
CN (2) | CN111093794B (en) |
WO (2) | WO2019098176A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN114699944A (en) * | 2022-02-18 | 2022-07-05 | 潍柴动力股份有限公司 | Steel wool mixer and diesel engine tail gas aftertreatment device with same |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2020218357A1 (en) * | 2019-04-23 | 2020-10-29 | ヤマシンフィルタ株式会社 | Filter device |
CN112156526A (en) * | 2020-08-24 | 2021-01-01 | 九江七所精密机电科技有限公司 | Double-precision filter with double signaling |
Family Cites Families (36)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5933452Y2 (en) * | 1981-06-19 | 1984-09-18 | 大幸機器株式会社 | fluid filtration equipment |
JPH06327909A (en) * | 1993-05-24 | 1994-11-29 | Yamashin Kogyo Kk | Capsule type filter device for liquid |
JP2001090701A (en) * | 1999-09-22 | 2001-04-03 | Komatsu Ltd | Filter device for operating oil tank |
US7014761B2 (en) * | 2002-06-07 | 2006-03-21 | Baldwin Filters, Inc. | Environmentally friendly dual lube venturi filter cartridge |
ITRE20030033A1 (en) * | 2003-03-31 | 2004-10-01 | Ufi Filters Spa | "BASE FOR FILTER CARTRIDGE FOR INTERNAL COMBUSTION ENGINES" |
JP4102246B2 (en) | 2003-04-28 | 2008-06-18 | 株式会社東芝 | Semiconductor device and manufacturing method thereof |
US7602815B2 (en) | 2003-09-04 | 2009-10-13 | Broadcom Corporation | Using network time protocol in voice over packet transmission |
DE602004020925D1 (en) * | 2003-12-22 | 2009-06-10 | Donaldson Co Inc | LIQUID FILTER ARRANGEMENT AND METHOD |
JP4414836B2 (en) | 2004-08-03 | 2010-02-10 | 和興フィルタテクノロジー株式会社 | filter |
DE202007006385U1 (en) | 2006-05-10 | 2007-09-20 | Hengst Gmbh & Co.Kg | Liquid filter with return valve in the clean-side flow channel |
DE102006036231A1 (en) * | 2006-08-03 | 2008-02-07 | Hydac Filtertechnik Gmbh | filter means |
US20100219113A1 (en) * | 2007-10-19 | 2010-09-02 | Mp Filtri S.P.A. | Device for Filtering Pressurized Oil |
JP4887317B2 (en) | 2008-03-10 | 2012-02-29 | 和興フィルタテクノロジー株式会社 | Oil filter |
JP2009214005A (en) * | 2008-03-10 | 2009-09-24 | Wako Filter Technology Kk | Oil filter |
JP4927772B2 (en) * | 2008-03-10 | 2012-05-09 | 和興フィルタテクノロジー株式会社 | Oil filter |
JP4927771B2 (en) * | 2008-03-10 | 2012-05-09 | 和興フィルタテクノロジー株式会社 | Oil filter |
JP5085523B2 (en) | 2008-12-24 | 2012-11-28 | 和興フィルタテクノロジー株式会社 | Oil filter |
DE102009050794A1 (en) * | 2009-10-27 | 2011-04-28 | Robert Bosch Gmbh | Suction return filter with dual function valve |
JP2011220363A (en) * | 2010-04-02 | 2011-11-04 | Yamashin-Filter Corp | Mounting structure of commutator, and filter device |
US11975279B2 (en) * | 2012-01-12 | 2024-05-07 | Davco Technology, Llc | Fluid filter assembly with a filter cartridge and housing interface |
CN103480190B (en) * | 2012-03-30 | 2017-03-01 | 康明斯过滤Ip公司 | There is the filter of filtration barrel body and corresponding filtration barrel body |
US9675911B2 (en) * | 2012-08-01 | 2017-06-13 | Andrey Yurievich Yazykov | Water intake filter |
DE102013004285B4 (en) * | 2013-03-13 | 2016-10-13 | Mann + Hummel Gmbh | Filter element with a built-in an end plate valve assembly |
JP6100052B2 (en) * | 2013-03-27 | 2017-03-22 | 和興フィルタテクノロジー株式会社 | Fluid filter |
FR3014703B1 (en) * | 2013-12-12 | 2016-07-01 | Filtrauto | FUEL FILTER WITH ADDITIVE RELEASE DEVICE |
US9527016B2 (en) * | 2014-01-24 | 2016-12-27 | Caterpillar Inc. | Filter element having vent tube and filter assembly |
DE102014102794B4 (en) * | 2014-03-03 | 2018-05-03 | Fsp Fluid Systems Partners Holding Ag | Filter device for filtering a hydraulic fluid |
DE102014017860A1 (en) * | 2014-12-03 | 2016-06-09 | Hydac Process Technology Gmbh | Filter device, hydraulic system and backwashing process |
JP6624819B2 (en) * | 2015-06-18 | 2019-12-25 | ヤマシンフィルタ株式会社 | Return filter |
JP6613101B2 (en) * | 2015-10-26 | 2019-11-27 | ヤマシンフィルタ株式会社 | Return filter |
JP6592329B2 (en) * | 2015-10-30 | 2019-10-16 | ヤマシンフィルタ株式会社 | Filter device |
KR101691556B1 (en) * | 2015-11-11 | 2017-01-09 | 말레동현필터시스템 주식회사 | Oil filter assembly having drain pin improved combination structure |
EP3287180B1 (en) * | 2016-08-25 | 2019-04-10 | Walter Stauffenberg Gmbh & Co. Kg | Suction return filter |
JP2018086625A (en) * | 2016-11-29 | 2018-06-07 | ヤマシンフィルタ株式会社 | Filter device and filtration device |
JP2018118204A (en) * | 2017-01-24 | 2018-08-02 | ヤマシンフィルタ株式会社 | Filter device |
JP6892295B2 (en) * | 2017-03-16 | 2021-06-23 | ヤマシンフィルタ株式会社 | Filter device and filtration device |
-
2018
- 2018-11-13 CN CN201880058987.9A patent/CN111093794B/en active Active
- 2018-11-13 KR KR1020207006658A patent/KR102651725B1/en active IP Right Grant
- 2018-11-13 CN CN201880049619.8A patent/CN110958907B/en active Active
- 2018-11-13 WO PCT/JP2018/041939 patent/WO2019098176A1/en unknown
- 2018-11-13 JP JP2019554217A patent/JP7219475B2/en active Active
- 2018-11-13 JP JP2019554216A patent/JP7187475B2/en active Active
- 2018-11-13 EP EP18878874.9A patent/EP3711837B1/en active Active
- 2018-11-13 EP EP18878564.6A patent/EP3711836B1/en active Active
- 2018-11-13 WO PCT/JP2018/041935 patent/WO2019098174A1/en unknown
- 2018-11-13 KR KR1020207006657A patent/KR102636377B1/en active IP Right Grant
-
2020
- 2020-04-06 US US16/840,507 patent/US11541338B2/en active Active
- 2020-04-06 US US16/840,511 patent/US11052336B2/en active Active
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN114699944A (en) * | 2022-02-18 | 2022-07-05 | 潍柴动力股份有限公司 | Steel wool mixer and diesel engine tail gas aftertreatment device with same |
Also Published As
Publication number | Publication date |
---|---|
CN111093794B (en) | 2022-05-13 |
JPWO2019098174A1 (en) | 2020-11-26 |
KR20200084317A (en) | 2020-07-10 |
EP3711836A1 (en) | 2020-09-23 |
KR20200084318A (en) | 2020-07-10 |
KR102636377B1 (en) | 2024-02-13 |
EP3711837A1 (en) | 2020-09-23 |
EP3711836B1 (en) | 2022-07-13 |
EP3711836A4 (en) | 2020-12-16 |
US20200230529A1 (en) | 2020-07-23 |
EP3711837B1 (en) | 2021-12-29 |
WO2019098176A1 (en) | 2019-05-23 |
JP7219475B2 (en) | 2023-02-08 |
JP7187475B2 (en) | 2022-12-12 |
WO2019098174A1 (en) | 2019-05-23 |
US11541338B2 (en) | 2023-01-03 |
CN110958907B (en) | 2021-10-22 |
US11052336B2 (en) | 2021-07-06 |
CN110958907A (en) | 2020-04-03 |
EP3711837A4 (en) | 2020-12-09 |
JPWO2019098176A1 (en) | 2020-11-19 |
CN111093794A (en) | 2020-05-01 |
KR102651725B1 (en) | 2024-03-26 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US11052336B2 (en) | Filter device | |
US10350527B2 (en) | Filter device and filtration device | |
CN107530600B (en) | Filter device | |
KR101945790B1 (en) | Automatic drain discharge apparatus | |
US10525386B2 (en) | Filter device | |
US10702808B2 (en) | Filter device and filtration device | |
US11465078B2 (en) | Filter device and filtration apparatus | |
US12025085B2 (en) | Tank device | |
US20220032216A1 (en) | Filter device | |
US9970594B2 (en) | Automatic drain | |
US20200215464A1 (en) | Filter device | |
JP4414836B2 (en) | filter | |
US4160735A (en) | Fluid filter bypass valve assembly |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: YAMASHIN-FILTER CORP., JAPAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KITAJIMA, NOBUYUKI;YAMAGUCHI, MITSUHIRO;REEL/FRAME:052316/0279 Effective date: 20200204 |
|
FEPP | Fee payment procedure |
Free format text: ENTITY STATUS SET TO UNDISCOUNTED (ORIGINAL EVENT CODE: BIG.); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
FEPP | Fee payment procedure |
Free format text: ENTITY STATUS SET TO SMALL (ORIGINAL EVENT CODE: SMAL); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: DOCKETED NEW CASE - READY FOR EXAMINATION |
|
FEPP | Fee payment procedure |
Free format text: ENTITY STATUS SET TO UNDISCOUNTED (ORIGINAL EVENT CODE: BIG.); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
FEPP | Fee payment procedure |
Free format text: PETITION RELATED TO MAINTENANCE FEES GRANTED (ORIGINAL EVENT CODE: PTGR); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: NOTICE OF ALLOWANCE MAILED -- APPLICATION RECEIVED IN OFFICE OF PUBLICATIONS |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: PUBLICATIONS -- ISSUE FEE PAYMENT RECEIVED |
|
STPP | Information on status: patent application and granting procedure in general |
Free format text: PUBLICATIONS -- ISSUE FEE PAYMENT VERIFIED |
|
STCF | Information on status: patent grant |
Free format text: PATENTED CASE |